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I'm about to smash my ST2k........Please stop me!

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  • Photon Collector
    People, I m at wit s end. I have been imaging with my ST2k imager for a couple years now. I have always had big problems with random hot (or bright) pixels. My
    Message 1 of 25 , Sep 30, 2006
      People, I'm at wit's end.
      I have been imaging with my ST2k imager for a couple years now. I have always had big problems with random hot (or bright) pixels. My images and darks have the usual consistent hot pixels that subtract out as they should. But both the images and the darks also have a large quantity of random hot pixels that differ from image to image and dark to dark. These random hot pixels do not subtract out because they pop up at random throughout the images and darks. The result is an image with many bright and dark pixels. Bright pixels remain in the image because the dark frame doesn't contain a corresponding bright pixel to subtract out. Dark pixels appear in the reduced image because the dark frame has bright pixels where there are none on the image.
      To prove to myself that the problem is real, I subtracted one dark frame from another dark frame shot in sequence. The resultant image should be very smooth. Instead it has bright and dark pixels, just like my images. As another test, I shot 10 darks in a row, of course all with the same temp and time settings. Then I opened them up in both Maxim and CCDSoft and ran a blink comparison. During the blink comparison, you can see that about 1/2 of the hot pixels are fixed in their position while the rest jump around all over the image. The same is true when doing a blink comparison of a series of raw images shot in sequence.
      I even went as far as upgrading my imaging chip from the older 2001 chip to the new and (supposedly) less noisy 2020 chip at great cost to me. The results are exactly the same.
      Here is an example of a completed image: http://publicmissiles.com/franku/2020_-25_f55_processed_NGC_7331.jpg
      It is a combination of 8, 20 minute exposures median combined after reduction using 10 median combined dark frames and the appropriate flat fields.
      If someone out there has a broadband connection (12 meg file!) and is willing to help, I have up-loaded a zip file containing a raw image, a flat field, and 3 dark frames. Try processing the image with the data I provided to see if you can get a clean image......I sure can't. Here is the zip file with everything you need: http://publicmissiles.com/franku/Raw_stuff.zip
      In the past I would spend an hour or two with the clone tool cleaning up every bad pixel. But I just can't believe this is what everyone else goes through. I never hear about problems similar to what I'm having. I hope it's just something I'm doing wrong but I can't imagine what it is. Is it possible that something in the observatory environment is causing the random hot pixels?



      ---Frank Rocketman Uroda

      [Non-text portions of this message have been removed]
    • George Sallit
      Frank, I had a look at your images and they do look a little noisier than my ST2K. Mine normally end up with just a few dark/bright pixels although I use a 10
      Message 2 of 25 , Oct 1, 2006
        Frank,

        I had a look at your images and they do look a little noisier than my ST2K.
        Mine normally end up with just a few dark/bright pixels although I use a 10
        minute exposure time due to my closeness to a major airport. My initial
        thoughts are that your images look like mine when I need to refresh the dark
        library.

        A couple of comments, are you certain there is no light leak? It should not
        give a problem with hot pixels but may make things worse.

        I compared the average noise levels in your camera and the standard
        deviation and they were not too dissimilar. Mine were (for 600 secs) 1000
        +/- 188 @-20C and yours (for 1200) 2040 +/- 431 @ -25C. Your gain is 0.64
        mine 0.55 so the numbers are not too far out.

        Have you tried taking the darks at the same time as the lights, there can
        sometimes be a difference if the outside air temp is higher for the darks
        than the lights?

        The other way of really reducing noise it to use a random shift between
        images so that the noise in the images does not coincide. It is possible to
        do this automatically with Maxim and auto dither or manually with the hand
        set (a bit more of a chore).

        Using blink comparison is normally not too helpful, particularly if the
        programme out-ranges. I also get a noisy looking dark frame if I subtract
        two images. If you have two sets of dark frames then median combine the
        first and then the second and then subtract them, that may give a better
        clue.

        It may be worth (and I suspect you may have already) try starting from
        scratch in a methodical way. Start by using Maxim (I know a change but it
        may be something subtle).

        Firstly take a set (10) of bias frames and then a set (10) of dark frames of
        about 2 mins.
        Now take a set (10) of light frames of 2mins.

        Now median combine the bias and darks and use them to calibrate the light
        frames. The median combine the calibrated light frames and see what results.
        If the result has few hot/dark pixels then OK. If not measure all the frames
        and see if there is anything odd about them. I can give you comparison data
        on my measurements if that helps so we can try and track down the issue.

        Now try extending the times of the dark and lights and see what happens. You
        should look to see when things get worse (cliff-edge effect) or whether the
        gradually get worse. This should help track down the issue(s).

        Sorry I do not have the magic bullet but your calibration approach is right
        and those images are more noisier than mine.

        -----Original Message-----
        From: ccd-newastro@yahoogroups.com
        [mailto:ccd-newastro@yahoogroups.com]On Behalf Of Photon Collector
        Sent: 01 October 2006 07:14
        To: ccd-newastro@yahoogroups.com
        Subject: [ccd-newastro] I'm about to smash my ST2k........Please stop
        me!


        People, I'm at wit's end.
        I have been imaging with my ST2k imager for a couple years now. I have
        always had big problems with random hot (or bright) pixels. My images and
        darks have the usual consistent hot pixels that subtract out as they should.
        But both the images and the darks also have a large quantity of random hot
        pixels that differ from image to image and dark to dark. These random hot
        pixels do not subtract out because they pop up at random throughout the
        images and darks. The result is an image with many bright and dark pixels.
        Bright pixels remain in the image because the dark frame doesn't contain a
        corresponding bright pixel to subtract out. Dark pixels appear in the
        reduced image because the dark frame has bright pixels where there are none
        on the image.
        To prove to myself that the problem is real, I subtracted one dark frame
        from another dark frame shot in sequence. The resultant image should be very
        smooth. Instead it has bright and dark pixels, just like my images. As
        another test, I shot 10 darks in a row, of course all with the same temp and
        time settings. Then I opened them up in both Maxim and CCDSoft and ran a
        blink comparison. During the blink comparison, you can see that about 1/2 of
        the hot pixels are fixed in their position while the rest jump around all
        over the image. The same is true when doing a blink comparison of a series
        of raw images shot in sequence.
        I even went as far as upgrading my imaging chip from the older 2001 chip to
        the new and (supposedly) less noisy 2020 chip at great cost to me. The
        results are exactly the same.
        Here is an example of a completed image:
        http://publicmissiles.com/franku/2020_-25_f55_processed_NGC_7331.jpg
        It is a combination of 8, 20 minute exposures median combined after
        reduction using 10 median combined dark frames and the appropriate flat
        fields.
        If someone out there has a broadband connection (12 meg file!) and is
        willing to help, I have up-loaded a zip file containing a raw image, a flat
        field, and 3 dark frames. Try processing the image with the data I provided
        to see if you can get a clean image......I sure can't. Here is the zip file
        with everything you need: http://publicmissiles.com/franku/Raw_stuff.zip
        In the past I would spend an hour or two with the clone tool cleaning up
        every bad pixel. But I just can't believe this is what everyone else goes
        through. I never hear about problems similar to what I'm having. I hope it's
        just something I'm doing wrong but I can't imagine what it is. Is it
        possible that something in the observatory environment is causing the random
        hot pixels?



        ---Frank Rocketman Uroda

        [Non-text portions of this message have been removed]





        Yahoo! Groups Links













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      • Terry Platt
        Hi Frank, Random hot pixels are usually data errors of some kind. For example, they could be due to interruptions of the camera download as other computer
        Message 3 of 25 , Oct 1, 2006
          Hi Frank,

          Random 'hot pixels' are usually data errors of some kind. For example, they could be due to interruptions of the camera download as other computer processes capture the bus. Is you control computer running free of other intensive applications? Network activity is a classic cause of random effects.

          Regards,
          Terry

          ----- Original Message -----
          From: Photon Collector
          To: ccd-newastro@yahoogroups.com
          Sent: Sunday, October 01, 2006 7:13 AM
          Subject: [ccd-newastro] I'm about to smash my ST2k........Please stop me!


          People, I'm at wit's end.
          I have been imaging with my ST2k imager for a couple years now. I have always had big problems with random hot (or bright) pixels. My images and darks have the usual consistent hot pixels that subtract out as they should. But both the images and the darks also have a large quantity of random hot pixels that differ from image to image and dark to dark. These random hot pixels do not subtract out because they pop up at random throughout the images and darks. The result is an image with many bright and dark pixels. Bright pixels remain in the image because the dark frame doesn't contain a corresponding bright pixel to subtract out. Dark pixels appear in the reduced image because the dark frame has bright pixels where there are none on the image.
          To prove to myself that the problem is real, I subtracted one dark frame from another dark frame shot in sequence. The resultant image should be very smooth. Instead it has bright and dark pixels, just like my images. As another test, I shot 10 darks in a row, of course all with the same temp and time settings. Then I opened them up in both Maxim and CCDSoft and ran a blink comparison. During the blink comparison, you can see that about 1/2 of the hot pixels are fixed in their position while the rest jump around all over the image. The same is true when doing a blink comparison of a series of raw images shot in sequence.
          I even went as far as upgrading my imaging chip from the older 2001 chip to the new and (supposedly) less noisy 2020 chip at great cost to me. The results are exactly the same.
          Here is an example of a completed image: http://publicmissiles.com/franku/2020_-25_f55_processed_NGC_7331.jpg
          It is a combination of 8, 20 minute exposures median combined after reduction using 10 median combined dark frames and the appropriate flat fields.
          If someone out there has a broadband connection (12 meg file!) and is willing to help, I have up-loaded a zip file containing a raw image, a flat field, and 3 dark frames. Try processing the image with the data I provided to see if you can get a clean image......I sure can't. Here is the zip file with everything you need: http://publicmissiles.com/franku/Raw_stuff.zip
          In the past I would spend an hour or two with the clone tool cleaning up every bad pixel. But I just can't believe this is what everyone else goes through. I never hear about problems similar to what I'm having. I hope it's just something I'm doing wrong but I can't imagine what it is. Is it possible that something in the observatory environment is causing the random hot pixels?

          ---Frank Rocketman Uroda

          [Non-text portions of this message have been removed]





          [Non-text portions of this message have been removed]
        • Mike Dodd
          ... At first I was going to suggest cosmic rays, but I don t think that is the case. I took a look at your dark frames, and you re right - there are lots of
          Message 4 of 25 , Oct 1, 2006
            > I shot 10 darks in a row, of course all with the same temp and time
            > settings. Then I opened them up in both Maxim and CCDSoft and ran a
            > blink comparison. During the blink comparison, you can see that about
            > 1/2 of the hot pixels are fixed in their position while the rest jump
            > around all over the image.

            At first I was going to suggest cosmic rays, but I don't think that is
            the case.

            I took a look at your dark frames, and you're right - there are lots of
            bright pixels moving between frames. Something strange is going on. Here
            are ADU levels from the same two pixels on all three darks:

            Coordinates Frame 3 Frame 4 Frame 5
            ----------- ------- ------- -------
            686,542 2,148 2,041 16,406
            705,563 12,797 13,158 2,020

            Notice how the 686,542 pixel's ADU remains at the 2K level for two
            frames, then jumps to 16K in the third. The opposite is true for the
            705,563 pixel. It has a high ADU for two frames, then drops in the third.

            Furthermore, it isn't just the really-bright pixels that are doing this.
            Many of the jumping pixels have ADUs only slightly higher than the
            (roughly) 2K background level.

            This sort of noise can be caused by unstable cooling. Your dark frame
            headers indicate they were exposed at -25C; what was the cooler power
            percentage? Generally, you should keep it below about 85% for stable
            cooling. If it was above that, I'm thinking that might be the source of
            the random bright pixels.

            Another issue might be light pollution. The SBIG cameras aren't
            light-tight, so ambient light can find its way inside. Even brief
            flashes could cause some low-level bright pixels, and changing locations
            would account for the jumping pixels. What was going on around the
            camera while the darks were being exposed?

            Fortunately, there are a couple of simple tests you can perform to help
            identify the source of the noise.

            1. Set up in a dark area and cool the camera to a point where the cooler
            power is below 85%. The exact temperature isn't important, so don't
            worry if you can't get to -25C. Take several 20-minute dark frames and
            see if there are fewer jumping pixels (there might be more noise, but
            most of the pixels should remain the same between frames). If so, then
            the problem is likely the cooler power level.

            2. If you still see a lot of jumping pixels, it's time to check for
            light pollution. Put the camera in the refrigerator and cool it to the
            same temperature as in test #1 (in the 'fridge, the cooler power should
            be very low). Now take several 20-minute exposures (don't open the
            refrigerator door) and check the noise pixels again. If there are fewer
            than test #1, you're dealing with a light leak.

            Finally, if you see approximately the same number of jumping pixels with
            these two tests, it might be time to have SBIG check the camera. Maybe
            the CCD chip isn't bonded effectively to the cooler plate, so even
            though the cooler is maintained at the set temperature, the chip isn't
            being cooled.

            Hope this helps.

            Mike
            --

            Mike Dodd
            Montpelier, VA (37 49'N, 77 42'W)
            Celestron CGE 9.25", SBIG ST-8XM
            http://astronomy.mdodd.com
          • Photon Collector
            I usually run CCDSoft and TheSky 6. I also control the laptop from the house using MS Remote Desktop via a network cable. I am running a series of tests now. I
            Message 5 of 25 , Oct 1, 2006
              I usually run CCDSoft and TheSky 6. I also control the laptop from the house using MS Remote Desktop via a network cable.
              I am running a series of tests now. I put the camera in a large cooler and wrapped the cooler with a heavy moving blanket. I also have the camera capped and set the Ha filter in place. Only CCDSoft is running. The dew heaters and mount drives are all off. Now I'm shooting a series of darks, three for each test.
              First test is with network cable unplugged.
              Next I will make a direct connection from the camera to the laptop via USB and bypass the hub.

              ---Frank Rocketman Uroda


              ----- Original Message -----
              From: Terry Platt
              To: ccd-newastro@yahoogroups.com
              Sent: Sunday, October 01, 2006 6:16 AM
              Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop me!


              Hi Frank,

              Random 'hot pixels' are usually data errors of some kind. For example, they could be due to interruptions of the camera download as other computer processes capture the bus. Is you control computer running free of other intensive applications? Network activity is a classic cause of random effects.

              Regards,
              Terry

              ----- Original Message -----
              From: Photon Collector
              To: ccd-newastro@yahoogroups.com
              Sent: Sunday, October 01, 2006 7:13 AM
              Subject: [ccd-newastro] I'm about to smash my ST2k........Please stop me!

              People, I'm at wit's end.
              I have been imaging with my ST2k imager for a couple years now. I have always had big problems with random hot (or bright) pixels. My images and darks have the usual consistent hot pixels that subtract out as they should. But both the images and the darks also have a large quantity of random hot pixels that differ from image to image and dark to dark. These random hot pixels do not subtract out because they pop up at random throughout the images and darks. The result is an image with many bright and dark pixels. Bright pixels remain in the image because the dark frame doesn't contain a corresponding bright pixel to subtract out. Dark pixels appear in the reduced image because the dark frame has bright pixels where there are none on the image.
              To prove to myself that the problem is real, I subtracted one dark frame from another dark frame shot in sequence. The resultant image should be very smooth. Instead it has bright and dark pixels, just like my images. As another test, I shot 10 darks in a row, of course all with the same temp and time settings. Then I opened them up in both Maxim and CCDSoft and ran a blink comparison. During the blink comparison, you can see that about 1/2 of the hot pixels are fixed in their position while the rest jump around all over the image. The same is true when doing a blink comparison of a series of raw images shot in sequence.
              I even went as far as upgrading my imaging chip from the older 2001 chip to the new and (supposedly) less noisy 2020 chip at great cost to me. The results are exactly the same.
              Here is an example of a completed image: http://publicmissiles.com/franku/2020_-25_f55_processed_NGC_7331.jpg
              It is a combination of 8, 20 minute exposures median combined after reduction using 10 median combined dark frames and the appropriate flat fields.
              If someone out there has a broadband connection (12 meg file!) and is willing to help, I have up-loaded a zip file containing a raw image, a flat field, and 3 dark frames. Try processing the image with the data I provided to see if you can get a clean image......I sure can't. Here is the zip file with everything you need: http://publicmissiles.com/franku/Raw_stuff.zip
              In the past I would spend an hour or two with the clone tool cleaning up every bad pixel. But I just can't believe this is what everyone else goes through. I never hear about problems similar to what I'm having. I hope it's just something I'm doing wrong but I can't imagine what it is. Is it possible that something in the observatory environment is causing the random hot pixels?

              ---Frank Rocketman Uroda

              [Non-text portions of this message have been removed]

              [Non-text portions of this message have been removed]





              [Non-text portions of this message have been removed]
            • Steve Reilly
              Hey Frank, I think you ll have your answer after running these test. I suspect the hub and or network will be the culprit. Steve ... From:
              Message 6 of 25 , Oct 1, 2006
                Hey Frank,

                I think you'll have your answer after running these test. I suspect the hub
                and or network will be the culprit.

                Steve

                -----Original Message-----
                From: ccd-newastro@yahoogroups.com [mailto:ccd-newastro@yahoogroups.com] On
                Behalf Of Photon Collector
                Sent: Sunday, October 01, 2006 10:37 AM
                To: ccd-newastro@yahoogroups.com
                Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop
                me!

                I usually run CCDSoft and TheSky 6. I also control the laptop from the house
                using MS Remote Desktop via a network cable.
                I am running a series of tests now. I put the camera in a large cooler and
                wrapped the cooler with a heavy moving blanket. I also have the camera
                capped and set the Ha filter in place. Only CCDSoft is running. The dew
                heaters and mount drives are all off. Now I'm shooting a series of darks,
                three for each test.
                First test is with network cable unplugged.
                Next I will make a direct connection from the camera to the laptop via USB
                and bypass the hub.

                ---Frank Rocketman Uroda


                ----- Original Message -----
                From: Terry Platt
                To: ccd-newastro@yahoogroups.com
                Sent: Sunday, October 01, 2006 6:16 AM
                Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop
                me!


                Hi Frank,

                Random 'hot pixels' are usually data errors of some kind. For example,
                they could be due to interruptions of the camera download as other computer
                processes capture the bus. Is you control computer running free of other
                intensive applications? Network activity is a classic cause of random
                effects.

                Regards,
                Terry

                ----- Original Message -----
                From: Photon Collector
                To: ccd-newastro@yahoogroups.com
                Sent: Sunday, October 01, 2006 7:13 AM
                Subject: [ccd-newastro] I'm about to smash my ST2k........Please stop me!

                People, I'm at wit's end.
                I have been imaging with my ST2k imager for a couple years now. I have
                always had big problems with random hot (or bright) pixels. My images and
                darks have the usual consistent hot pixels that subtract out as they should.
                But both the images and the darks also have a large quantity of random hot
                pixels that differ from image to image and dark to dark. These random hot
                pixels do not subtract out because they pop up at random throughout the
                images and darks. The result is an image with many bright and dark pixels.
                Bright pixels remain in the image because the dark frame doesn't contain a
                corresponding bright pixel to subtract out. Dark pixels appear in the
                reduced image because the dark frame has bright pixels where there are none
                on the image.
                To prove to myself that the problem is real, I subtracted one dark frame
                from another dark frame shot in sequence. The resultant image should be very
                smooth. Instead it has bright and dark pixels, just like my images. As
                another test, I shot 10 darks in a row, of course all with the same temp and
                time settings. Then I opened them up in both Maxim and CCDSoft and ran a
                blink comparison. During the blink comparison, you can see that about 1/2 of
                the hot pixels are fixed in their position while the rest jump around all
                over the image. The same is true when doing a blink comparison of a series
                of raw images shot in sequence.
                I even went as far as upgrading my imaging chip from the older 2001 chip
                to the new and (supposedly) less noisy 2020 chip at great cost to me. The
                results are exactly the same.
                Here is an example of a completed image:
                http://publicmissiles.com/franku/2020_-25_f55_processed_NGC_7331.jpg
                It is a combination of 8, 20 minute exposures median combined after
                reduction using 10 median combined dark frames and the appropriate flat
                fields.
                If someone out there has a broadband connection (12 meg file!) and is
                willing to help, I have up-loaded a zip file containing a raw image, a flat
                field, and 3 dark frames. Try processing the image with the data I provided
                to see if you can get a clean image......I sure can't. Here is the zip file
                with everything you need: http://publicmissiles.com/franku/Raw_stuff.zip
                In the past I would spend an hour or two with the clone tool cleaning up
                every bad pixel. But I just can't believe this is what everyone else goes
                through. I never hear about problems similar to what I'm having. I hope it's
                just something I'm doing wrong but I can't imagine what it is. Is it
                possible that something in the observatory environment is causing the random
                hot pixels?

                ---Frank Rocketman Uroda

                [Non-text portions of this message have been removed]

                [Non-text portions of this message have been removed]





                [Non-text portions of this message have been removed]





                Yahoo! Groups Links
              • Bert Katzung
                Hi Frank: I ve had that sort of salt & pepper artifact problem on occasion with my ST10-XME; don t know what causes it or cures it, seems to have its own
                Message 7 of 25 , Oct 1, 2006
                  Hi Frank:
                  I've had that sort of salt & pepper artifact problem on occasion with my
                  ST10-XME; don't know what causes it or cures it, seems to have its own
                  schedule.
                  On the positive side, I find I can get rid of them with the hot and cold
                  pixel removal tools in MaxIm. Extra steps, but they clean up pretty
                  well---never have to use the clone tool in Photoshop.
                  Bert

                  katzung1@...
                  www.astronomy-images.com
                  www.visionlightgallery.com/katzung/

                  ----- Original Message -----
                  From: "Photon Collector" <photoncollector@...>
                  To: <ccd-newastro@yahoogroups.com>
                  Sent: Saturday, September 30, 2006 11:13 PM
                  Subject: [ccd-newastro] I'm about to smash my ST2k........Please stop me!


                  > People, I'm at wit's end.
                  > I have been imaging with my ST2k imager for a couple years now. I have
                  > always had big problems with random hot (or bright) pixels. My images and
                  > darks have the usual consistent hot pixels that subtract out as they
                  > should. But both the images and the darks also have a large quantity of
                  > random hot pixels that differ from image to image and dark to dark. These
                  > random hot pixels do not subtract out because they pop up at random
                  > throughout the images and darks. The result is an image with many bright
                  > and dark pixels. Bright pixels remain in the image because the dark frame
                  > doesn't contain a corresponding bright pixel to subtract out. Dark pixels
                  > appear in the reduced image because the dark frame has bright pixels where
                  > there are none on the image.
                  > To prove to myself that the problem is real, I subtracted one dark frame
                  > from another dark frame shot in sequence. The resultant image should be
                  > very smooth. Instead it has bright and dark pixels, just like my images.
                  > As another test, I shot 10 darks in a row, of course all with the same
                  > temp and time settings. Then I opened them up in both Maxim and CCDSoft
                  > and ran a blink comparison. During the blink comparison, you can see that
                  > about 1/2 of the hot pixels are fixed in their position while the rest
                  > jump around all over the image. The same is true when doing a blink
                  > comparison of a series of raw images shot in sequence.
                  > I even went as far as upgrading my imaging chip from the older 2001 chip
                  > to the new and (supposedly) less noisy 2020 chip at great cost to me. The
                  > results are exactly the same.
                  > Here is an example of a completed image:
                  > http://publicmissiles.com/franku/2020_-25_f55_processed_NGC_7331.jpg
                  > It is a combination of 8, 20 minute exposures median combined after
                  > reduction using 10 median combined dark frames and the appropriate flat
                  > fields.
                  > If someone out there has a broadband connection (12 meg file!) and is
                  > willing to help, I have up-loaded a zip file containing a raw image, a
                  > flat field, and 3 dark frames. Try processing the image with the data I
                  > provided to see if you can get a clean image......I sure can't. Here is
                  > the zip file with everything you need:
                  > http://publicmissiles.com/franku/Raw_stuff.zip
                  > In the past I would spend an hour or two with the clone tool cleaning up
                  > every bad pixel. But I just can't believe this is what everyone else goes
                  > through. I never hear about problems similar to what I'm having. I hope
                  > it's just something I'm doing wrong but I can't imagine what it is. Is it
                  > possible that something in the observatory environment is causing the
                  > random hot pixels?
                  >
                  >
                  >
                  > ---Frank Rocketman Uroda
                  >
                • Photon Collector
                  The hot and cold pixel removal tools in MaxIM didn t do much at all. Instead I used the median kernel filter in MaxIM on each of my subframe right after
                  Message 8 of 25 , Oct 1, 2006
                    The hot and cold pixel removal tools in MaxIM didn't do much at all. Instead I used the median kernel filter in MaxIM on each of my subframe right after initial reduction. I then did a median combine of the 8 subframes.
                    The image is MUCH better! Take a look but please excuse my quick post-processing. Nothing was done to remove bad pixels in PS.
                    http://publicmissiles.com/franku/2020_-25_f55_processed2_NGC_7331.jpg

                    Of course, this is not a fix of the root cause but it's many times better than ever before. I'm still running my equipment tests.

                    ---Frank Rocketman Uroda


                    ----- Original Message -----
                    From: Bert Katzung
                    To: ccd-newastro@yahoogroups.com
                    Sent: Sunday, October 01, 2006 11:52 AM
                    Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop me!


                    Hi Frank:
                    I've had that sort of salt & pepper artifact problem on occasion with my
                    ST10-XME; don't know what causes it or cures it, seems to have its own
                    schedule.
                    On the positive side, I find I can get rid of them with the hot and cold
                    pixel removal tools in MaxIm. Extra steps, but they clean up pretty
                    well---never have to use the clone tool in Photoshop.
                    Bert

                    katzung1@...
                    www.astronomy-images.com
                    www.visionlightgallery.com/katzung/

                    ----- Original Message -----
                    From: "Photon Collector" <photoncollector@...>
                    To: <ccd-newastro@yahoogroups.com>
                    Sent: Saturday, September 30, 2006 11:13 PM
                    Subject: [ccd-newastro] I'm about to smash my ST2k........Please stop me!

                    > People, I'm at wit's end.
                    > I have been imaging with my ST2k imager for a couple years now. I have
                    > always had big problems with random hot (or bright) pixels. My images and
                    > darks have the usual consistent hot pixels that subtract out as they
                    > should. But both the images and the darks also have a large quantity of
                    > random hot pixels that differ from image to image and dark to dark. These
                    > random hot pixels do not subtract out because they pop up at random
                    > throughout the images and darks. The result is an image with many bright
                    > and dark pixels. Bright pixels remain in the image because the dark frame
                    > doesn't contain a corresponding bright pixel to subtract out. Dark pixels
                    > appear in the reduced image because the dark frame has bright pixels where
                    > there are none on the image.
                    > To prove to myself that the problem is real, I subtracted one dark frame
                    > from another dark frame shot in sequence. The resultant image should be
                    > very smooth. Instead it has bright and dark pixels, just like my images.
                    > As another test, I shot 10 darks in a row, of course all with the same
                    > temp and time settings. Then I opened them up in both Maxim and CCDSoft
                    > and ran a blink comparison. During the blink comparison, you can see that
                    > about 1/2 of the hot pixels are fixed in their position while the rest
                    > jump around all over the image. The same is true when doing a blink
                    > comparison of a series of raw images shot in sequence.
                    > I even went as far as upgrading my imaging chip from the older 2001 chip
                    > to the new and (supposedly) less noisy 2020 chip at great cost to me. The
                    > results are exactly the same.
                    > Here is an example of a completed image:
                    > http://publicmissiles.com/franku/2020_-25_f55_processed_NGC_7331.jpg
                    > It is a combination of 8, 20 minute exposures median combined after
                    > reduction using 10 median combined dark frames and the appropriate flat
                    > fields.
                    > If someone out there has a broadband connection (12 meg file!) and is
                    > willing to help, I have up-loaded a zip file containing a raw image, a
                    > flat field, and 3 dark frames. Try processing the image with the data I
                    > provided to see if you can get a clean image......I sure can't. Here is
                    > the zip file with everything you need:
                    > http://publicmissiles.com/franku/Raw_stuff.zip
                    > In the past I would spend an hour or two with the clone tool cleaning up
                    > every bad pixel. But I just can't believe this is what everyone else goes
                    > through. I never hear about problems similar to what I'm having. I hope
                    > it's just something I'm doing wrong but I can't imagine what it is. Is it
                    > possible that something in the observatory environment is causing the
                    > random hot pixels?
                    >
                    >
                    >
                    > ---Frank Rocketman Uroda
                    >





                    [Non-text portions of this message have been removed]
                  • Wodaski - Yahoo
                    I can t speak to the cause of your problem, although I think Terry s idea about CPU cycles possible being an issue is worth examination. When was the last time
                    Message 9 of 25 , Oct 1, 2006
                      I can't speak to the cause of your problem, although I think Terry's
                      idea about CPU cycles possible being an issue is worth examination.

                      When was the last time you updated your SBIG drivers? Older versions of
                      the SBIG drivers, when loaded into your camera, would cause you to get
                      poorer performance.

                      How sure are you of the voltage going into the camera? If available, try
                      an alternate power supply.

                      From a processing angle, download Russell Croman's RC-Astro Console for
                      MaxIm DL. It contains a routine for identifying and dealing with random
                      pixel variations. I used it with my STL-11000 before SBIG provided new
                      drivers that eliminated the random pixel problem (well, mostly). To
                      download:

                      http://www.rc-astro.com/resources/rc_console.html

                      Your long exposures are also potentially an issue, especially if this is
                      related to power supply fluctuations. What kind of variations do you get
                      with 5- or 10-minute images/darks?

                      Also, just a point: if you are going to take eight images, then take at
                      least 8 darks. Otherwise, your darks are adding more noise than they
                      should to the final result.

                      As others have suggested, the ABG chips in the SBIG cameras perform
                      noticeably better if you dither across several pixels. This alone can
                      make a significant difference by offsetting the pixels and allowing
                      rejection algorithms to function more effectively.

                      Ron Wodaski


                      Photon Collector wrote:
                      > The hot and cold pixel removal tools in MaxIM didn't do much at all. Instead I used the median kernel filter in MaxIM on each of my subframe right after initial reduction. I then did a median combine of the 8 subframes.
                      > The image is MUCH better! Take a look but please excuse my quick post-processing. Nothing was done to remove bad pixels in PS.
                      > http://publicmissiles.com/franku/2020_-25_f55_processed2_NGC_7331.jpg
                      >
                      > Of course, this is not a fix of the root cause but it's many times better than ever before. I'm still running my equipment tests.
                      >
                      > ---Frank Rocketman Uroda
                      >
                      >
                      > ----- Original Message -----
                      > From: Bert Katzung
                      > To: ccd-newastro@yahoogroups.com
                      > Sent: Sunday, October 01, 2006 11:52 AM
                      > Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop me!
                      >
                      >
                      > Hi Frank:
                      > I've had that sort of salt & pepper artifact problem on occasion with my
                      > ST10-XME; don't know what causes it or cures it, seems to have its own
                      > schedule.
                      > On the positive side, I find I can get rid of them with the hot and cold
                      > pixel removal tools in MaxIm. Extra steps, but they clean up pretty
                      > well---never have to use the clone tool in Photoshop.
                      > Bert
                      >
                      > katzung1@...
                      > www.astronomy-images.com
                      > www.visionlightgallery.com/katzung/
                      >
                      > ----- Original Message -----
                      > From: "Photon Collector" <photoncollector@...>
                      > To: <ccd-newastro@yahoogroups.com>
                      > Sent: Saturday, September 30, 2006 11:13 PM
                      > Subject: [ccd-newastro] I'm about to smash my ST2k........Please stop me!
                      >
                      > > People, I'm at wit's end.
                      > > I have been imaging with my ST2k imager for a couple years now. I have
                      > > always had big problems with random hot (or bright) pixels. My images and
                      > > darks have the usual consistent hot pixels that subtract out as they
                      > > should. But both the images and the darks also have a large quantity of
                      > > random hot pixels that differ from image to image and dark to dark. These
                      > > random hot pixels do not subtract out because they pop up at random
                      > > throughout the images and darks. The result is an image with many bright
                      > > and dark pixels. Bright pixels remain in the image because the dark frame
                      > > doesn't contain a corresponding bright pixel to subtract out. Dark pixels
                      > > appear in the reduced image because the dark frame has bright pixels where
                      > > there are none on the image.
                      > > To prove to myself that the problem is real, I subtracted one dark frame
                      > > from another dark frame shot in sequence. The resultant image should be
                      > > very smooth. Instead it has bright and dark pixels, just like my images.
                      > > As another test, I shot 10 darks in a row, of course all with the same
                      > > temp and time settings. Then I opened them up in both Maxim and CCDSoft
                      > > and ran a blink comparison. During the blink comparison, you can see that
                      > > about 1/2 of the hot pixels are fixed in their position while the rest
                      > > jump around all over the image. The same is true when doing a blink
                      > > comparison of a series of raw images shot in sequence.
                      > > I even went as far as upgrading my imaging chip from the older 2001 chip
                      > > to the new and (supposedly) less noisy 2020 chip at great cost to me. The
                      > > results are exactly the same.
                      > > Here is an example of a completed image:
                      > > http://publicmissiles.com/franku/2020_-25_f55_processed_NGC_7331.jpg
                      > > It is a combination of 8, 20 minute exposures median combined after
                      > > reduction using 10 median combined dark frames and the appropriate flat
                      > > fields.
                      > > If someone out there has a broadband connection (12 meg file!) and is
                      > > willing to help, I have up-loaded a zip file containing a raw image, a
                      > > flat field, and 3 dark frames. Try processing the image with the data I
                      > > provided to see if you can get a clean image......I sure can't. Here is
                      > > the zip file with everything you need:
                      > > http://publicmissiles.com/franku/Raw_stuff.zip
                      > > In the past I would spend an hour or two with the clone tool cleaning up
                      > > every bad pixel. But I just can't believe this is what everyone else goes
                      > > through. I never hear about problems similar to what I'm having. I hope
                      > > it's just something I'm doing wrong but I can't imagine what it is. Is it
                      > > possible that something in the observatory environment is causing the
                      > > random hot pixels?
                      > >
                      > >
                      > >
                      > > ---Frank Rocketman Uroda
                      > >
                      >
                      >
                      >
                      >
                      >
                      > [Non-text portions of this message have been removed]
                      >
                      >
                      >
                      >
                      > Yahoo! Groups Links
                      >
                      >
                      >
                      >
                      >
                      >
                      >
                      >
                      >
                      >

                      --

                      Ron Wodaski
                      New Astronomy Press
                      http://www.newastro.com
                    • Photon Collector
                      Replies within text below......... I can t speak to the cause of your problem, although I think Terry s idea about CPU cycles possible being an issue is worth
                      Message 10 of 25 , Oct 1, 2006
                        Replies within text below.........

                        I can't speak to the cause of your problem, although I think Terry's
                        idea about CPU cycles possible being an issue is worth examination.
                        ...I'm using an IBM ThinkPad A21m running at 650 MHz with 512 meg RAM. I only run CCDSoft and TheSky 6 (with all Real Sky stuff turned off).

                        When was the last time you updated your SBIG drivers? Older versions of
                        the SBIG drivers, when loaded into your camera, would cause you to get
                        poorer performance.
                        ...I'd say the drivers are a year old or so.

                        How sure are you of the voltage going into the camera? If available, try
                        an alternate power supply.
                        ...I'm using the SBIG power supply that came with the camera. I don't have a second one to try.

                        From a processing angle, download Russell Croman's RC-Astro Console for
                        MaxIm DL. It contains a routine for identifying and dealing with random
                        pixel variations. I used it with my STL-11000 before SBIG provided new
                        drivers that eliminated the random pixel problem (well, mostly). To
                        download:

                        http://www.rc-astro.com/resources/rc_console.html
                        ...I'll give it a try.

                        Your long exposures are also potentially an issue, especially if this is
                        related to power supply fluctuations. What kind of variations do you get
                        with 5- or 10-minute images/darks?
                        ...I never compared them. I will though.

                        Also, just a point: if you are going to take eight images, then take at
                        least 8 darks. Otherwise, your darks are adding more noise than they
                        should to the final result.
                        ...I use 10-12 darks and 20 flat fields at all times.

                        As others have suggested, the ABG chips in the SBIG cameras perform
                        noticeably better if you dither across several pixels. This alone can
                        make a significant difference by offsetting the pixels and allowing
                        rejection algorithms to function more effectively.
                        ...I had no improvement the last time I tried that but I'm willing to try it again.

                        Ron Wodaski


                        ---Frank Rocketman Uroda

                        [Non-text portions of this message have been removed]
                      • Wodaski - Yahoo
                        See my comments below. Ron ... -- That s very slow by today s standards. Could be an issue. ... There have been major changes during that year. An update is
                        Message 11 of 25 , Oct 1, 2006
                          See my comments below.

                          Ron

                          Photon Collector wrote:
                          > Replies within text below.........
                          >
                          > I can't speak to the cause of your problem, although I think Terry's
                          > idea about CPU cycles possible being an issue is worth examination.
                          > ...I'm using an IBM ThinkPad A21m running at 650 MHz with 512 meg RAM. I only run CCDSoft and TheSky 6 (with all Real Sky stuff turned off).
                          >
                          --> That's very slow by today's standards. Could be an issue.
                          > When was the last time you updated your SBIG drivers? Older versions of
                          > the SBIG drivers, when loaded into your camera, would cause you to get
                          > poorer performance.
                          > ...I'd say the drivers are a year old or so.
                          >
                          There have been major changes during that year. An update is well worth
                          it. You will need to make new darks/bias.
                          > How sure are you of the voltage going into the camera? If available, try
                          > an alternate power supply.
                          > ...I'm using the SBIG power supply that came with the camera. I don't have a second one to try.
                          >
                          > From a processing angle, download Russell Croman's RC-Astro Console for
                          > MaxIm DL. It contains a routine for identifying and dealing with random
                          > pixel variations. I used it with my STL-11000 before SBIG provided new
                          > drivers that eliminated the random pixel problem (well, mostly). To
                          > download:
                          >
                          > http://www.rc-astro.com/resources/rc_console.html
                          > ...I'll give it a try.
                          >
                          > Your long exposures are also potentially an issue, especially if this is
                          > related to power supply fluctuations. What kind of variations do you get
                          > with 5- or 10-minute images/darks?
                          > ...I never compared them. I will though.
                          >
                          > Also, just a point: if you are going to take eight images, then take at
                          > least 8 darks. Otherwise, your darks are adding more noise than they
                          > should to the final result.
                          > ...I use 10-12 darks and 20 flat fields at all times.
                          >
                          > As others have suggested, the ABG chips in the SBIG cameras perform
                          > noticeably better if you dither across several pixels. This alone can
                          > make a significant difference by offsetting the pixels and allowing
                          > rejection algorithms to function more effectively.
                          > ...I had no improvement the last time I tried that but I'm willing to try it again.
                          >
                          --> Then we can look at your data rejection methods. Dithering works
                          great if you use the right tools in the right way.
                          > Ron Wodaski
                          >
                          >
                          > ---Frank Rocketman Uroda
                          >
                          > [Non-text portions of this message have been removed]
                          >
                          >
                          >
                          >
                          > Yahoo! Groups Links
                          >
                          >
                          >
                          >
                          >
                          >
                          >
                          >
                          >
                          >

                          --

                          Ron Wodaski
                          New Astronomy Press
                          http://www.newastro.com
                        • Photon Collector
                          I m sad to say that my test results are bad news. I took 3x15 minute dark frames at -15 degrees for each of the following: Original configuration as a base
                          Message 12 of 25 , Oct 1, 2006
                            I'm sad to say that my test results are bad news.
                            I took 3x15 minute dark frames at -15 degrees for each of the following:
                            Original configuration as a base line.
                            With network off and unplugged.
                            With network off and direct USB connection.
                            With network off and direct USB connection and all other items (heaters, mount, etc.) turned off.

                            None of the above made any difference. All of the darks look the same as the base line dark. Same amount of fixed hot pixels and about the same amount of random bright pixels.

                            ---Frank Rocketman Uroda


                            ----- Original Message -----
                            From: Steve Reilly
                            To: ccd-newastro@yahoogroups.com
                            Sent: Sunday, October 01, 2006 11:32 AM
                            Subject: RE: [ccd-newastro] I'm about to smash my ST2k........Please stop me!


                            Hey Frank,

                            I think you'll have your answer after running these test. I suspect the hub
                            and or network will be the culprit.

                            Steve

                            -----Original Message-----
                            From: ccd-newastro@yahoogroups.com [mailto:ccd-newastro@yahoogroups.com] On
                            Behalf Of Photon Collector
                            Sent: Sunday, October 01, 2006 10:37 AM
                            To: ccd-newastro@yahoogroups.com
                            Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop
                            me!

                            I usually run CCDSoft and TheSky 6. I also control the laptop from the house
                            using MS Remote Desktop via a network cable.
                            I am running a series of tests now. I put the camera in a large cooler and
                            wrapped the cooler with a heavy moving blanket. I also have the camera
                            capped and set the Ha filter in place. Only CCDSoft is running. The dew
                            heaters and mount drives are all off. Now I'm shooting a series of darks,
                            three for each test.
                            First test is with network cable unplugged.
                            Next I will make a direct connection from the camera to the laptop via USB
                            and bypass the hub.

                            ---Frank Rocketman Uroda

                            ----- Original Message -----
                            From: Terry Platt
                            To: ccd-newastro@yahoogroups.com
                            Sent: Sunday, October 01, 2006 6:16 AM
                            Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop
                            me!

                            Hi Frank,

                            Random 'hot pixels' are usually data errors of some kind. For example,
                            they could be due to interruptions of the camera download as other computer
                            processes capture the bus. Is you control computer running free of other
                            intensive applications? Network activity is a classic cause of random
                            effects.

                            Regards,
                            Terry

                            ----- Original Message -----
                            From: Photon Collector
                            To: ccd-newastro@yahoogroups.com
                            Sent: Sunday, October 01, 2006 7:13 AM
                            Subject: [ccd-newastro] I'm about to smash my ST2k........Please stop me!

                            People, I'm at wit's end.
                            I have been imaging with my ST2k imager for a couple years now. I have
                            always had big problems with random hot (or bright) pixels. My images and
                            darks have the usual consistent hot pixels that subtract out as they should.
                            But both the images and the darks also have a large quantity of random hot
                            pixels that differ from image to image and dark to dark. These random hot
                            pixels do not subtract out because they pop up at random throughout the
                            images and darks. The result is an image with many bright and dark pixels.
                            Bright pixels remain in the image because the dark frame doesn't contain a
                            corresponding bright pixel to subtract out. Dark pixels appear in the
                            reduced image because the dark frame has bright pixels where there are none
                            on the image.
                            To prove to myself that the problem is real, I subtracted one dark frame
                            from another dark frame shot in sequence. The resultant image should be very
                            smooth. Instead it has bright and dark pixels, just like my images. As
                            another test, I shot 10 darks in a row, of course all with the same temp and
                            time settings. Then I opened them up in both Maxim and CCDSoft and ran a
                            blink comparison. During the blink comparison, you can see that about 1/2 of
                            the hot pixels are fixed in their position while the rest jump around all
                            over the image. The same is true when doing a blink comparison of a series
                            of raw images shot in sequence.
                            I even went as far as upgrading my imaging chip from the older 2001 chip
                            to the new and (supposedly) less noisy 2020 chip at great cost to me. The
                            results are exactly the same.
                            Here is an example of a completed image:
                            http://publicmissiles.com/franku/2020_-25_f55_processed_NGC_7331.jpg
                            It is a combination of 8, 20 minute exposures median combined after
                            reduction using 10 median combined dark frames and the appropriate flat
                            fields.
                            If someone out there has a broadband connection (12 meg file!) and is
                            willing to help, I have up-loaded a zip file containing a raw image, a flat
                            field, and 3 dark frames. Try processing the image with the data I provided
                            to see if you can get a clean image......I sure can't. Here is the zip file
                            with everything you need: http://publicmissiles.com/franku/Raw_stuff.zip
                            In the past I would spend an hour or two with the clone tool cleaning up
                            every bad pixel. But I just can't believe this is what everyone else goes
                            through. I never hear about problems similar to what I'm having. I hope it's
                            just something I'm doing wrong but I can't imagine what it is. Is it
                            possible that something in the observatory environment is causing the random
                            hot pixels?

                            ---Frank Rocketman Uroda

                            [Non-text portions of this message have been removed]

                            [Non-text portions of this message have been removed]

                            [Non-text portions of this message have been removed]

                            Yahoo! Groups Links





                            [Non-text portions of this message have been removed]
                          • Mike Dodd
                            ... Then you might want to update the camera drivers, as Ron and others suggested. I remember one fix a few months ago that sounded fairly major. Don t know if
                            Message 13 of 25 , Oct 1, 2006
                              > None of the above made any difference. All of the darks look the same
                              > as the base line dark. Same amount of fixed hot pixels and about the
                              > same amount of random bright pixels.

                              Then you might want to update the camera drivers, as Ron and others
                              suggested. I remember one fix a few months ago that sounded fairly
                              major. Don't know if it will fix your problem, but it's definitely worth
                              a try.

                              Mike

                              --

                              Mike Dodd
                              Montpelier, VA (37 49'N, 77 42'W)
                              Celestron CGE 9.25", SBIG ST-8XM
                              http://astronomy.mdodd.com
                            • L.Knoll
                              Rocketman: I agree with Steve. I think you have some kind of BW/transmission/network problem, or maybe even an EMI problem from some nearby source of transient
                              Message 14 of 25 , Oct 1, 2006
                                Rocketman:

                                I agree with Steve. I think you have some kind of BW/transmission/network problem, or maybe even an EMI problem from some nearby source of transient impulses (dome motor, nearby industrial motors, bad hydro transmission lines, etc.).

                                Is all your stuff shielded correctly wrt signal/equipment grounds? There is a big difference between signal and equipment grounding as far as ground noise and ground bounce in digital systems.

                                Is there any chance of you borrowing another same brand/model camera from someone in a local astronomy club?

                                All else aside ... I feel your pain. I'll courier you a sledge hammer if you want. :)

                                I am an electronics technologist and by no means an experienced engineering astronomy 'guru', but this sounds too weird. Assuming your camera is OK as far as production line parameter windows go ... there are many sources of random noise impules, both external and internal to your camera, so make sure your shielding and grounding is correct.

                                Also, try another computer.

                                Cheers,
                                Leonard Knoll



                                ----- Original Message -----
                                From: Photon Collector
                                To: ccd-newastro@yahoogroups.com
                                Sent: Sunday, October 01, 2006 4:16 PM
                                Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop me!


                                I'm sad to say that my test results are bad news.
                                I took 3x15 minute dark frames at -15 degrees for each of the following:
                                Original configuration as a base line.
                                With network off and unplugged.
                                With network off and direct USB connection.
                                With network off and direct USB connection and all other items (heaters, mount, etc.) turned off.

                                None of the above made any difference. All of the darks look the same as the base line dark. Same amount of fixed hot pixels and about the same amount of random bright pixels.

                                ---Frank Rocketman Uroda

                                ----- Original Message -----
                                From: Steve Reilly
                                To: ccd-newastro@yahoogroups.com
                                Sent: Sunday, October 01, 2006 11:32 AM
                                Subject: RE: [ccd-newastro] I'm about to smash my ST2k........Please stop me!

                                Hey Frank,

                                I think you'll have your answer after running these test. I suspect the hub
                                and or network will be the culprit.

                                Steve

                                -----Original Message-----
                                From: ccd-newastro@yahoogroups.com [mailto:ccd-newastro@yahoogroups.com] On
                                Behalf Of Photon Collector
                                Sent: Sunday, October 01, 2006 10:37 AM
                                To: ccd-newastro@yahoogroups.com
                                Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop
                                me!

                                I usually run CCDSoft and TheSky 6. I also control the laptop from the house
                                using MS Remote Desktop via a network cable.
                                I am running a series of tests now. I put the camera in a large cooler and
                                wrapped the cooler with a heavy moving blanket. I also have the camera
                                capped and set the Ha filter in place. Only CCDSoft is running. The dew
                                heaters and mount drives are all off. Now I'm shooting a series of darks,
                                three for each test.
                                First test is with network cable unplugged.
                                Next I will make a direct connection from the camera to the laptop via USB
                                and bypass the hub.

                                ---Frank Rocketman Uroda

                                ----- Original Message -----
                                From: Terry Platt
                                To: ccd-newastro@yahoogroups.com
                                Sent: Sunday, October 01, 2006 6:16 AM
                                Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop
                                me!

                                Hi Frank,

                                Random 'hot pixels' are usually data errors of some kind. For example,
                                they could be due to interruptions of the camera download as other computer
                                processes capture the bus. Is you control computer running free of other
                                intensive applications? Network activity is a classic cause of random
                                effects.

                                Regards,
                                Terry

                                ----- Original Message -----
                                From: Photon Collector
                                To: ccd-newastro@yahoogroups.com
                                Sent: Sunday, October 01, 2006 7:13 AM
                                Subject: [ccd-newastro] I'm about to smash my ST2k........Please stop me!

                                People, I'm at wit's end.
                                I have been imaging with my ST2k imager for a couple years now. I have
                                always had big problems with random hot (or bright) pixels. My images and
                                darks have the usual consistent hot pixels that subtract out as they should.
                                But both the images and the darks also have a large quantity of random hot
                                pixels that differ from image to image and dark to dark. These random hot
                                pixels do not subtract out because they pop up at random throughout the
                                images and darks. The result is an image with many bright and dark pixels.
                                Bright pixels remain in the image because the dark frame doesn't contain a
                                corresponding bright pixel to subtract out. Dark pixels appear in the
                                reduced image because the dark frame has bright pixels where there are none
                                on the image.
                                To prove to myself that the problem is real, I subtracted one dark frame
                                from another dark frame shot in sequence. The resultant image should be very
                                smooth. Instead it has bright and dark pixels, just like my images. As
                                another test, I shot 10 darks in a row, of course all with the same temp and
                                time settings. Then I opened them up in both Maxim and CCDSoft and ran a
                                blink comparison. During the blink comparison, you can see that about 1/2 of
                                the hot pixels are fixed in their position while the rest jump around all
                                over the image. The same is true when doing a blink comparison of a series
                                of raw images shot in sequence.
                                I even went as far as upgrading my imaging chip from the older 2001 chip
                                to the new and (supposedly) less noisy 2020 chip at great cost to me. The
                                results are exactly the same.
                                Here is an example of a completed image:
                                http://publicmissiles.com/franku/2020_-25_f55_processed_NGC_7331.jpg
                                It is a combination of 8, 20 minute exposures median combined after
                                reduction using 10 median combined dark frames and the appropriate flat
                                fields.
                                If someone out there has a broadband connection (12 meg file!) and is
                                willing to help, I have up-loaded a zip file containing a raw image, a flat
                                field, and 3 dark frames. Try processing the image with the data I provided
                                to see if you can get a clean image......I sure can't. Here is the zip file
                                with everything you need: http://publicmissiles.com/franku/Raw_stuff.zip
                                In the past I would spend an hour or two with the clone tool cleaning up
                                every bad pixel. But I just can't believe this is what everyone else goes
                                through. I never hear about problems similar to what I'm having. I hope it's
                                just something I'm doing wrong but I can't imagine what it is. Is it
                                possible that something in the observatory environment is causing the random
                                hot pixels?

                                ---Frank Rocketman Uroda

                                [Non-text portions of this message have been removed]

                                [Non-text portions of this message have been removed]

                                [Non-text portions of this message have been removed]

                                Yahoo! Groups Links

                                [Non-text portions of this message have been removed]





                                [Non-text portions of this message have been removed]
                              • Photon Collector
                                I already downloaded it and will install it after dinner. The sky is clear tonight so I ll be able to test it right away. ... From: Mike Dodd To:
                                Message 15 of 25 , Oct 1, 2006
                                  I already downloaded it and will install it after dinner. The sky is clear tonight so I'll be able to test it right away.

                                  ---Frank Rocketman Uroda


                                  ----- Original Message -----
                                  From: Mike Dodd
                                  To: ccd-newastro@yahoogroups.com
                                  Sent: Sunday, October 01, 2006 5:17 PM
                                  Subject: [ccd-newastro] Re: I'm about to smash my ST2k........Please stop me!


                                  > None of the above made any difference. All of the darks look the same
                                  > as the base line dark. Same amount of fixed hot pixels and about the
                                  > same amount of random bright pixels.

                                  Then you might want to update the camera drivers, as Ron and others
                                  suggested. I remember one fix a few months ago that sounded fairly
                                  major. Don't know if it will fix your problem, but it's definitely worth
                                  a try.

                                  Mike

                                  --

                                  Mike Dodd
                                  Montpelier, VA (37 49'N, 77 42'W)
                                  Celestron CGE 9.25", SBIG ST-8XM
                                  http://astronomy.mdodd.com




                                  [Non-text portions of this message have been removed]
                                • Photon Collector
                                  Thanks for the input but I ve been using this camera for over 2 years now. The observatory is less than 1 year old. This camera has always had this problem
                                  Message 16 of 25 , Oct 1, 2006
                                    Thanks for the input but I've been using this camera for over 2 years now. The observatory is less than 1 year old. This camera has always had this problem with MANY different mobile and semi-permanent set-ups. About the only thing that hasn't changed since I began using the camera is the USB hub and the laptop. Today I bypassed the hub with no change. That leaves the laptop and the camera itself as suspect. I kinda doubt it's the laptop. It's been solid as a rock for years now. I did update the SBIG camera drivers today though. The old drivers were over a year old and some folks have said that there have been major improvements with the new drivers. Maybe that will make a difference. The sky is clear tonight so I'll be out there!

                                    ---Frank Rocketman Uroda


                                    ----- Original Message -----
                                    From: L.Knoll
                                    To: ccd-newastro@yahoogroups.com
                                    Sent: Sunday, October 01, 2006 6:01 PM
                                    Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop me!


                                    Rocketman:

                                    I agree with Steve. I think you have some kind of BW/transmission/network problem, or maybe even an EMI problem from some nearby source of transient impulses (dome motor, nearby industrial motors, bad hydro transmission lines, etc.).

                                    Is all your stuff shielded correctly wrt signal/equipment grounds? There is a big difference between signal and equipment grounding as far as ground noise and ground bounce in digital systems.

                                    Is there any chance of you borrowing another same brand/model camera from someone in a local astronomy club?

                                    All else aside ... I feel your pain. I'll courier you a sledge hammer if you want. :)

                                    I am an electronics technologist and by no means an experienced engineering astronomy 'guru', but this sounds too weird. Assuming your camera is OK as far as production line parameter windows go ... there are many sources of random noise impules, both external and internal to your camera, so make sure your shielding and grounding is correct.

                                    Also, try another computer.

                                    Cheers,
                                    Leonard Knoll

                                    ----- Original Message -----
                                    From: Photon Collector
                                    To: ccd-newastro@yahoogroups.com
                                    Sent: Sunday, October 01, 2006 4:16 PM
                                    Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop me!

                                    I'm sad to say that my test results are bad news.
                                    I took 3x15 minute dark frames at -15 degrees for each of the following:
                                    Original configuration as a base line.
                                    With network off and unplugged.
                                    With network off and direct USB connection.
                                    With network off and direct USB connection and all other items (heaters, mount, etc.) turned off.

                                    None of the above made any difference. All of the darks look the same as the base line dark. Same amount of fixed hot pixels and about the same amount of random bright pixels.

                                    ---Frank Rocketman Uroda

                                    ----- Original Message -----
                                    From: Steve Reilly
                                    To: ccd-newastro@yahoogroups.com
                                    Sent: Sunday, October 01, 2006 11:32 AM
                                    Subject: RE: [ccd-newastro] I'm about to smash my ST2k........Please stop me!

                                    Hey Frank,

                                    I think you'll have your answer after running these test. I suspect the hub
                                    and or network will be the culprit.

                                    Steve

                                    -----Original Message-----
                                    From: ccd-newastro@yahoogroups.com [mailto:ccd-newastro@yahoogroups.com] On
                                    Behalf Of Photon Collector
                                    Sent: Sunday, October 01, 2006 10:37 AM
                                    To: ccd-newastro@yahoogroups.com
                                    Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop
                                    me!

                                    I usually run CCDSoft and TheSky 6. I also control the laptop from the house
                                    using MS Remote Desktop via a network cable.
                                    I am running a series of tests now. I put the camera in a large cooler and
                                    wrapped the cooler with a heavy moving blanket. I also have the camera
                                    capped and set the Ha filter in place. Only CCDSoft is running. The dew
                                    heaters and mount drives are all off. Now I'm shooting a series of darks,
                                    three for each test.
                                    First test is with network cable unplugged.
                                    Next I will make a direct connection from the camera to the laptop via USB
                                    and bypass the hub.

                                    ---Frank Rocketman Uroda

                                    ----- Original Message -----
                                    From: Terry Platt
                                    To: ccd-newastro@yahoogroups.com
                                    Sent: Sunday, October 01, 2006 6:16 AM
                                    Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop
                                    me!

                                    Hi Frank,

                                    Random 'hot pixels' are usually data errors of some kind. For example,
                                    they could be due to interruptions of the camera download as other computer
                                    processes capture the bus. Is you control computer running free of other
                                    intensive applications? Network activity is a classic cause of random
                                    effects.

                                    Regards,
                                    Terry

                                    ----- Original Message -----
                                    From: Photon Collector
                                    To: ccd-newastro@yahoogroups.com
                                    Sent: Sunday, October 01, 2006 7:13 AM
                                    Subject: [ccd-newastro] I'm about to smash my ST2k........Please stop me!

                                    People, I'm at wit's end.
                                    I have been imaging with my ST2k imager for a couple years now. I have
                                    always had big problems with random hot (or bright) pixels. My images and
                                    darks have the usual consistent hot pixels that subtract out as they should.
                                    But both the images and the darks also have a large quantity of random hot
                                    pixels that differ from image to image and dark to dark. These random hot
                                    pixels do not subtract out because they pop up at random throughout the
                                    images and darks. The result is an image with many bright and dark pixels.
                                    Bright pixels remain in the image because the dark frame doesn't contain a
                                    corresponding bright pixel to subtract out. Dark pixels appear in the
                                    reduced image because the dark frame has bright pixels where there are none
                                    on the image.
                                    To prove to myself that the problem is real, I subtracted one dark frame
                                    from another dark frame shot in sequence. The resultant image should be very
                                    smooth. Instead it has bright and dark pixels, just like my images. As
                                    another test, I shot 10 darks in a row, of course all with the same temp and
                                    time settings. Then I opened them up in both Maxim and CCDSoft and ran a
                                    blink comparison. During the blink comparison, you can see that about 1/2 of
                                    the hot pixels are fixed in their position while the rest jump around all
                                    over the image. The same is true when doing a blink comparison of a series
                                    of raw images shot in sequence.
                                    I even went as far as upgrading my imaging chip from the older 2001 chip
                                    to the new and (supposedly) less noisy 2020 chip at great cost to me. The
                                    results are exactly the same.
                                    Here is an example of a completed image:
                                    http://publicmissiles.com/franku/2020_-25_f55_processed_NGC_7331.jpg
                                    It is a combination of 8, 20 minute exposures median combined after
                                    reduction using 10 median combined dark frames and the appropriate flat
                                    fields.
                                    If someone out there has a broadband connection (12 meg file!) and is
                                    willing to help, I have up-loaded a zip file containing a raw image, a flat
                                    field, and 3 dark frames. Try processing the image with the data I provided
                                    to see if you can get a clean image......I sure can't. Here is the zip file
                                    with everything you need: http://publicmissiles.com/franku/Raw_stuff.zip
                                    In the past I would spend an hour or two with the clone tool cleaning up
                                    every bad pixel. But I just can't believe this is what everyone else goes
                                    through. I never hear about problems similar to what I'm having. I hope it's
                                    just something I'm doing wrong but I can't imagine what it is. Is it
                                    possible that something in the observatory environment is causing the random
                                    hot pixels?

                                    ---Frank Rocketman Uroda

                                    [Non-text portions of this message have been removed]

                                    [Non-text portions of this message have been removed]

                                    [Non-text portions of this message have been removed]

                                    Yahoo! Groups Links

                                    [Non-text portions of this message have been removed]

                                    [Non-text portions of this message have been removed]





                                    [Non-text portions of this message have been removed]
                                  • W. W. Mathis
                                    Leonard: The grounding issue leaves me totally confused. If some of the equiptment operates off house current, some of it operates off 12 v battery, etc,
                                    Message 17 of 25 , Oct 1, 2006
                                      Leonard:

                                      The "grounding" issue leaves me totally confused. If some of the equiptment operates off house current, some of it operates off 12 v battery, etc,
                                      what is "ground"? the house current is returned eventually to earth ground; the battery current is returned to the neg. term. on the battery -- and therefore floats wih respect to earth ground... and I may eventually buy a little generator to power everything, and its ground _must_ be returned to earth ground.... aarrgh! How do you untangle all these things? oh, and what is a "ground loop"?

                                      Ward Mathis
                                      ----- Original Message -----
                                      From: L.Knoll
                                      To: ccd-newastro@yahoogroups.com
                                      Sent: Sunday, October 01, 2006 4:01 PM
                                      Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop me!


                                      Rocketman:

                                      I agree with Steve. I think you have some kind of BW/transmission/network problem, or maybe even an EMI problem from some nearby source of transient impulses (dome motor, nearby industrial motors, bad hydro transmission lines, etc.).

                                      Is all your stuff shielded correctly wrt signal/equipment grounds? There is a big difference between signal and equipment grounding as far as ground noise and ground bounce in digital systems.

                                      Is there any chance of you borrowing another same brand/model camera from someone in a local astronomy club?

                                      All else aside ... I feel your pain. I'll courier you a sledge hammer if you want. :)

                                      I am an electronics technologist and by no means an experienced engineering astronomy 'guru', but this sounds too weird. Assuming your camera is OK as far as production line parameter windows go ... there are many sources of random noise impules, both external and internal to your camera, so make sure your shielding and grounding is correct.

                                      Also, try another computer.

                                      Cheers,
                                      Leonard Knoll

                                      ----- Original Message -----
                                      From: Photon Collector
                                      To: ccd-newastro@yahoogroups.com
                                      Sent: Sunday, October 01, 2006 4:16 PM
                                      Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop me!

                                      I'm sad to say that my test results are bad news.
                                      I took 3x15 minute dark frames at -15 degrees for each of the following:
                                      Original configuration as a base line.
                                      With network off and unplugged.
                                      With network off and direct USB connection.
                                      With network off and direct USB connection and all other items (heaters, mount, etc.) turned off.

                                      None of the above made any difference. All of the darks look the same as the base line dark. Same amount of fixed hot pixels and about the same amount of random bright pixels.

                                      ---Frank Rocketman Uroda

                                      ----- Original Message -----
                                      From: Steve Reilly
                                      To: ccd-newastro@yahoogroups.com
                                      Sent: Sunday, October 01, 2006 11:32 AM
                                      Subject: RE: [ccd-newastro] I'm about to smash my ST2k........Please stop me!

                                      Hey Frank,

                                      I think you'll have your answer after running these test. I suspect the hub
                                      and or network will be the culprit.

                                      Steve

                                      -----Original Message-----
                                      From: ccd-newastro@yahoogroups.com [mailto:ccd-newastro@yahoogroups.com] On
                                      Behalf Of Photon Collector
                                      Sent: Sunday, October 01, 2006 10:37 AM
                                      To: ccd-newastro@yahoogroups.com
                                      Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop
                                      me!

                                      I usually run CCDSoft and TheSky 6. I also control the laptop from the house
                                      using MS Remote Desktop via a network cable.
                                      I am running a series of tests now. I put the camera in a large cooler and
                                      wrapped the cooler with a heavy moving blanket. I also have the camera
                                      capped and set the Ha filter in place. Only CCDSoft is running. The dew
                                      heaters and mount drives are all off. Now I'm shooting a series of darks,
                                      three for each test.
                                      First test is with network cable unplugged.
                                      Next I will make a direct connection from the camera to the laptop via USB
                                      and bypass the hub.

                                      ---Frank Rocketman Uroda

                                      ----- Original Message -----
                                      From: Terry Platt
                                      To: ccd-newastro@yahoogroups.com
                                      Sent: Sunday, October 01, 2006 6:16 AM
                                      Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop
                                      me!

                                      Hi Frank,

                                      Random 'hot pixels' are usually data errors of some kind. For example,
                                      they could be due to interruptions of the camera download as other computer
                                      processes capture the bus. Is you control computer running free of other
                                      intensive applications? Network activity is a classic cause of random
                                      effects.

                                      Regards,
                                      Terry

                                      ----- Original Message -----
                                      From: Photon Collector
                                      To: ccd-newastro@yahoogroups.com
                                      Sent: Sunday, October 01, 2006 7:13 AM
                                      Subject: [ccd-newastro] I'm about to smash my ST2k........Please stop me!

                                      People, I'm at wit's end.
                                      I have been imaging with my ST2k imager for a couple years now. I have
                                      always had big problems with random hot (or bright) pixels. My images and
                                      darks have the usual consistent hot pixels that subtract out as they should.
                                      But both the images and the darks also have a large quantity of random hot
                                      pixels that differ from image to image and dark to dark. These random hot
                                      pixels do not subtract out because they pop up at random throughout the
                                      images and darks. The result is an image with many bright and dark pixels.
                                      Bright pixels remain in the image because the dark frame doesn't contain a
                                      corresponding bright pixel to subtract out. Dark pixels appear in the
                                      reduced image because the dark frame has bright pixels where there are none
                                      on the image.
                                      To prove to myself that the problem is real, I subtracted one dark frame
                                      from another dark frame shot in sequence. The resultant image should be very
                                      smooth. Instead it has bright and dark pixels, just like my images. As
                                      another test, I shot 10 darks in a row, of course all with the same temp and
                                      time settings. Then I opened them up in both Maxim and CCDSoft and ran a
                                      blink comparison. During the blink comparison, you can see that about 1/2 of
                                      the hot pixels are fixed in their position while the rest jump around all
                                      over the image. The same is true when doing a blink comparison of a series
                                      of raw images shot in sequence.
                                      I even went as far as upgrading my imaging chip from the older 2001 chip
                                      to the new and (supposedly) less noisy 2020 chip at great cost to me. The
                                      results are exactly the same.
                                      Here is an example of a completed image:
                                      http://publicmissiles.com/franku/2020_-25_f55_processed_NGC_7331.jpg
                                      It is a combination of 8, 20 minute exposures median combined after
                                      reduction using 10 median combined dark frames and the appropriate flat
                                      fields.
                                      If someone out there has a broadband connection (12 meg file!) and is
                                      willing to help, I have up-loaded a zip file containing a raw image, a flat
                                      field, and 3 dark frames. Try processing the image with the data I provided
                                      to see if you can get a clean image......I sure can't. Here is the zip file
                                      with everything you need: http://publicmissiles.com/franku/Raw_stuff.zip
                                      In the past I would spend an hour or two with the clone tool cleaning up
                                      every bad pixel. But I just can't believe this is what everyone else goes
                                      through. I never hear about problems similar to what I'm having. I hope it's
                                      just something I'm doing wrong but I can't imagine what it is. Is it
                                      possible that something in the observatory environment is causing the random
                                      hot pixels?

                                      ---Frank Rocketman Uroda

                                      [Non-text portions of this message have been removed]

                                      [Non-text portions of this message have been removed]

                                      [Non-text portions of this message have been removed]

                                      Yahoo! Groups Links

                                      [Non-text portions of this message have been removed]

                                      [Non-text portions of this message have been removed]





                                      [Non-text portions of this message have been removed]
                                    • rhtrembl
                                      In order to help you on this problem, I conducted a number of test today: I took a series of 20 dark frame on a ST8E parallel port on a compaq presario. I got
                                      Message 18 of 25 , Oct 1, 2006
                                        In order to help you on this problem,
                                        I conducted a number of test today:
                                        I took a series of 20 dark frame on a ST8E parallel port
                                        on a compaq presario. I got some random noise but the amplitude
                                        was fairly the same on 5 dark frames. say average noise is 120.
                                        I got peak at 320.
                                        I then conducted similar test with my st10xme using ubs interface.
                                        I then got peak at 1300 wich is 10fold that of the st8e.
                                        all this has been done at -10C.
                                        Any other st8E or st10xme with the same results?
                                        p.s. My st8 has just been overhaul a month ago at sbig where they
                                        replaced the interface board.
                                        Hope this help.
                                        Robert


                                        --- In ccd-newastro@yahoogroups.com, "Photon Collector"
                                        <photoncollector@...> wrote:
                                        >
                                        > People, I'm at wit's end.
                                        > I have been imaging with my ST2k imager for a couple years now. I
                                        have always had big problems with random hot (or bright) pixels. My
                                        images and darks have the usual consistent hot pixels that subtract
                                        out as they should. But both the images and the darks also have a
                                        large quantity of random hot pixels that differ from image to image
                                        and dark to dark. These random hot pixels do not subtract out
                                        because they pop up at random throughout the images and darks. The
                                        result is an image with many bright and dark pixels. Bright pixels
                                        remain in the image because the dark frame doesn't contain a
                                        corresponding bright pixel to subtract out. Dark pixels appear in
                                        the reduced image because the dark frame has bright pixels where
                                        there are none on the image.
                                        > To prove to myself that the problem is real, I subtracted one dark
                                        frame from another dark frame shot in sequence. The resultant image
                                        should be very smooth. Instead it has bright and dark pixels, just
                                        like my images. As another test, I shot 10 darks in a row, of course
                                        all with the same temp and time settings. Then I opened them up in
                                        both Maxim and CCDSoft and ran a blink comparison. During the blink
                                        comparison, you can see that about 1/2 of the hot pixels are fixed
                                        in their position while the rest jump around all over the image. The
                                        same is true when doing a blink comparison of a series of raw images
                                        shot in sequence.
                                        > I even went as far as upgrading my imaging chip from the older
                                        2001 chip to the new and (supposedly) less noisy 2020 chip at great
                                        cost to me. The results are exactly the same.
                                        > Here is an example of a completed image:
                                        http://publicmissiles.com/franku/2020_-25_f55_processed_NGC_7331.jpg
                                        > It is a combination of 8, 20 minute exposures median combined
                                        after reduction using 10 median combined dark frames and the
                                        appropriate flat fields.
                                        > If someone out there has a broadband connection (12 meg file!) and
                                        is willing to help, I have up-loaded a zip file containing a raw
                                        image, a flat field, and 3 dark frames. Try processing the image
                                        with the data I provided to see if you can get a clean image......I
                                        sure can't. Here is the zip file with everything you need:
                                        http://publicmissiles.com/franku/Raw_stuff.zip
                                        > In the past I would spend an hour or two with the clone tool
                                        cleaning up every bad pixel. But I just can't believe this is what
                                        everyone else goes through. I never hear about problems similar to
                                        what I'm having. I hope it's just something I'm doing wrong but I
                                        can't imagine what it is. Is it possible that something in the
                                        observatory environment is causing the random hot pixels?
                                        >
                                        >
                                        >
                                        > ---Frank Rocketman Uroda
                                        >
                                        > [Non-text portions of this message have been removed]
                                        >
                                      • L.Knoll
                                        Hi Ward: There are web resources and many, many, many books, at all levels of complexity on grounding in electrical systems. It s a whole world onto itself
                                        Message 19 of 25 , Oct 2, 2006
                                          Hi Ward:

                                          There are web resources and many, many, many books, at all levels of complexity on 'grounding' in electrical systems. It's a whole world onto itself in electrical engineering. This is actually not a trivial topic whatsoever so rather than blather on about it (since it's only indirectly on topic in this group) I'll send you a separate email. Electrical design engineers put a significant amount of effort into grounding and signal isolation so that we don't have to be overly concerned when we hook up all our astronomy (or stereo, or whatever) products.

                                          An electrical current 'loop' (it may be in a 'ground' or other conductor) is formed when one current is split between two paths which of course converge at each end (thus making a 'loop'). One common way for this to happen is when a shielded cable is plugged into something and its shield acts as an additional path for some object's ground current to flow though, usually somewhere where you don't want it to flow. That current can modulate or cause voltage gradients in the grounds of other circuits or radiate energy into them. For instance, if a portion of some intrument's return current (possibly with switching transients) somehow managed to flow through the shield of a camera USB cable, that might cause random image signal transmission noise problems.

                                          There, I stayed on topic. :)

                                          Cheers,
                                          Leonard





                                          ----- Original Message -----
                                          From: W. W. Mathis
                                          To: ccd-newastro@yahoogroups.com
                                          Sent: Sunday, October 01, 2006 8:15 PM
                                          Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop me!


                                          Leonard:

                                          The "grounding" issue leaves me totally confused. If some of the equiptment operates off house current, some of it operates off 12 v battery, etc,
                                          what is "ground"? the house current is returned eventually to earth ground; the battery current is returned to the neg. term. on the battery -- and therefore floats wih respect to earth ground... and I may eventually buy a little generator to power everything, and its ground _must_ be returned to earth ground.... aarrgh! How do you untangle all these things? oh, and what is a "ground loop"?

                                          Ward Mathis
                                          ----- Original Message -----
                                          From: L.Knoll
                                          To: ccd-newastro@yahoogroups.com
                                          Sent: Sunday, October 01, 2006 4:01 PM
                                          Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop me!

                                          Rocketman:

                                          I agree with Steve. I think you have some kind of BW/transmission/network problem, or maybe even an EMI problem from some nearby source of transient impulses (dome motor, nearby industrial motors, bad hydro transmission lines, etc.).

                                          Is all your stuff shielded correctly wrt signal/equipment grounds? There is a big difference between signal and equipment grounding as far as ground noise and ground bounce in digital systems.

                                          Is there any chance of you borrowing another same brand/model camera from someone in a local astronomy club?

                                          All else aside ... I feel your pain. I'll courier you a sledge hammer if you want. :)

                                          I am an electronics technologist and by no means an experienced engineering astronomy 'guru', but this sounds too weird. Assuming your camera is OK as far as production line parameter windows go ... there are many sources of random noise impules, both external and internal to your camera, so make sure your shielding and grounding is correct.

                                          Also, try another computer.

                                          Cheers,
                                          Leonard Knoll

                                          ----- Original Message -----
                                          From: Photon Collector
                                          To: ccd-newastro@yahoogroups.com
                                          Sent: Sunday, October 01, 2006 4:16 PM
                                          Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop me!

                                          I'm sad to say that my test results are bad news.
                                          I took 3x15 minute dark frames at -15 degrees for each of the following:
                                          Original configuration as a base line.
                                          With network off and unplugged.
                                          With network off and direct USB connection.
                                          With network off and direct USB connection and all other items (heaters, mount, etc.) turned off.

                                          None of the above made any difference. All of the darks look the same as the base line dark. Same amount of fixed hot pixels and about the same amount of random bright pixels.

                                          ---Frank Rocketman Uroda

                                          ----- Original Message -----
                                          From: Steve Reilly
                                          To: ccd-newastro@yahoogroups.com
                                          Sent: Sunday, October 01, 2006 11:32 AM
                                          Subject: RE: [ccd-newastro] I'm about to smash my ST2k........Please stop me!

                                          Hey Frank,

                                          I think you'll have your answer after running these test. I suspect the hub
                                          and or network will be the culprit.

                                          Steve

                                          -----Original Message-----
                                          From: ccd-newastro@yahoogroups.com [mailto:ccd-newastro@yahoogroups.com] On
                                          Behalf Of Photon Collector
                                          Sent: Sunday, October 01, 2006 10:37 AM
                                          To: ccd-newastro@yahoogroups.com
                                          Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop
                                          me!

                                          I usually run CCDSoft and TheSky 6. I also control the laptop from the house
                                          using MS Remote Desktop via a network cable.
                                          I am running a series of tests now. I put the camera in a large cooler and
                                          wrapped the cooler with a heavy moving blanket. I also have the camera
                                          capped and set the Ha filter in place. Only CCDSoft is running. The dew
                                          heaters and mount drives are all off. Now I'm shooting a series of darks,
                                          three for each test.
                                          First test is with network cable unplugged.
                                          Next I will make a direct connection from the camera to the laptop via USB
                                          and bypass the hub.

                                          ---Frank Rocketman Uroda

                                          ----- Original Message -----
                                          From: Terry Platt
                                          To: ccd-newastro@yahoogroups.com
                                          Sent: Sunday, October 01, 2006 6:16 AM
                                          Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop
                                          me!

                                          Hi Frank,

                                          Random 'hot pixels' are usually data errors of some kind. For example,
                                          they could be due to interruptions of the camera download as other computer
                                          processes capture the bus. Is you control computer running free of other
                                          intensive applications? Network activity is a classic cause of random
                                          effects.

                                          Regards,
                                          Terry

                                          ----- Original Message -----
                                          From: Photon Collector
                                          To: ccd-newastro@yahoogroups.com
                                          Sent: Sunday, October 01, 2006 7:13 AM
                                          Subject: [ccd-newastro] I'm about to smash my ST2k........Please stop me!

                                          People, I'm at wit's end.
                                          I have been imaging with my ST2k imager for a couple years now. I have
                                          always had big problems with random hot (or bright) pixels. My images and
                                          darks have the usual consistent hot pixels that subtract out as they should.
                                          But both the images and the darks also have a large quantity of random hot
                                          pixels that differ from image to image and dark to dark. These random hot
                                          pixels do not subtract out because they pop up at random throughout the
                                          images and darks. The result is an image with many bright and dark pixels.
                                          Bright pixels remain in the image because the dark frame doesn't contain a
                                          corresponding bright pixel to subtract out. Dark pixels appear in the
                                          reduced image because the dark frame has bright pixels where there are none
                                          on the image.
                                          To prove to myself that the problem is real, I subtracted one dark frame
                                          from another dark frame shot in sequence. The resultant image should be very
                                          smooth. Instead it has bright and dark pixels, just like my images. As
                                          another test, I shot 10 darks in a row, of course all with the same temp and
                                          time settings. Then I opened them up in both Maxim and CCDSoft and ran a
                                          blink comparison. During the blink comparison, you can see that about 1/2 of
                                          the hot pixels are fixed in their position while the rest jump around all
                                          over the image. The same is true when doing a blink comparison of a series
                                          of raw images shot in sequence.
                                          I even went as far as upgrading my imaging chip from the older 2001 chip
                                          to the new and (supposedly) less noisy 2020 chip at great cost to me. The
                                          results are exactly the same.
                                          Here is an example of a completed image:
                                          http://publicmissiles.com/franku/2020_-25_f55_processed_NGC_7331.jpg
                                          It is a combination of 8, 20 minute exposures median combined after
                                          reduction using 10 median combined dark frames and the appropriate flat
                                          fields.
                                          If someone out there has a broadband connection (12 meg file!) and is
                                          willing to help, I have up-loaded a zip file containing a raw image, a flat
                                          field, and 3 dark frames. Try processing the image with the data I provided
                                          to see if you can get a clean image......I sure can't. Here is the zip file
                                          with everything you need: http://publicmissiles.com/franku/Raw_stuff.zip
                                          In the past I would spend an hour or two with the clone tool cleaning up
                                          every bad pixel. But I just can't believe this is what everyone else goes
                                          through. I never hear about problems similar to what I'm having. I hope it's
                                          just something I'm doing wrong but I can't imagine what it is. Is it
                                          possible that something in the observatory environment is causing the random
                                          hot pixels?

                                          ---Frank Rocketman Uroda

                                          [Non-text portions of this message have been removed]

                                          [Non-text portions of this message have been removed]

                                          [Non-text portions of this message have been removed]

                                          Yahoo! Groups Links

                                          [Non-text portions of this message have been removed]

                                          [Non-text portions of this message have been removed]

                                          [Non-text portions of this message have been removed]





                                          [Non-text portions of this message have been removed]
                                        • Roger Hamlett
                                          ... Ground , has two distinct meanings. Generically, the ground in a circuit, is the point which voltages are referenced to. This is often connected to
                                          Message 20 of 25 , Oct 2, 2006
                                            > Leonard:
                                            >
                                            > The "grounding" issue leaves me totally confused. If some of the
                                            > equiptment operates off house current, some of it operates off 12 v
                                            > battery, etc, what is "ground"? the house current is returned
                                            > eventually to earth ground; the battery current is returned to the
                                            > neg. term. on the battery -- and therefore floats wih respect to earth
                                            > ground... and I may eventually buy a little generator to power
                                            > everything,
                                            > and its ground _must_ be returned to earth ground.... aarrgh! How do
                                            > you untangle all these things? oh, and what is a "ground loop"?
                                            > <snipped>
                                            'Ground', has two distinct meanings. Generically, the 'ground' in a
                                            circuit, is the point which voltages are referenced to. This is often
                                            connected to 'ground' (the local 'mains' safety/reference).
                                            So you can have a 'ground point', in a completely isolated circuit, and
                                            this still makes sense (I tend to tell people to seperate the concept of
                                            'ground', from 'earth', and also to use a distinctive term to make the
                                            segregation obvious - so an isolated part of a circuit, might have it's
                                            'ground', called 'ISGND' - isolated signal ground).
                                            In your case, the 12v battery 0v terminal, is the 'system ground' for this
                                            part of the unit.
                                            The big problem, is when there are multiple different 'ground paths'. If
                                            (for instance), you have a signal cable betwen two parts of a system, and
                                            both the 'parts', have their own 'grounds', and then these are linked by
                                            the cable, what happens?. The answer depends on the resistances involved in
                                            the cables, the resistance between the 'grounds', and the actual current
                                            involved. If (as is commonly the case...), the 'grounds' have slightly
                                            different voltages present ('earth', is not a perfect conductor...), the
                                            current, finds the lowest resistance path through the cable between the
                                            units, and current will be flowing through the cable as a result of having
                                            the two distinct 'ground' points. This voltage can result in unwanted
                                            signals being generated. This is why if you look at the circuits for
                                            systems that are likely to have problems from this (audio/video systems in
                                            particular), you will see local ground reference areas (usually 'planes' on
                                            the PCB for example), with just one ground path back to the main reference
                                            point, usually using a 'star' shaped ground layout (you want to avoid
                                            'tree' type ground layouts, since the current flows then encourage voltage
                                            differences to exist along the tree branches...). You will also see in the
                                            same systems, the cable 'shield', commonly connected at only one end of
                                            each connection.

                                            Best Wishes
                                          • W. W. Mathis
                                            Frank: I ve been thinking about your problem. I can see that a chip might have something wrong with a pixel that would give a hot pixel. But this hot
                                            Message 21 of 25 , Oct 2, 2006
                                              Frank: I've been thinking about your problem. I can see that a chip might have something wrong with a pixel that would give a "hot" pixel. But this hot pixel will be hot from now until doomsday, since it is an inherent defect in the chip. Random pixels that pop up hot in one photo and then don't in another photo can _only_ be due to random noise. So it seems to me that you should be looking for electrical problems that make the transmission "noisy". Poor connections, bad grounding, cross talk between wires, etc.
                                              . The computer will not accept info until it is ready to deal with it, so one program "Locking" another program out of memory really can't happen.

                                              Ward Mathis
                                              ----- Original Message -----
                                              From: Photon Collector
                                              To: ccd-newastro@yahoogroups.com
                                              Sent: Sunday, October 01, 2006 11:59 AM
                                              Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop me!


                                              The hot and cold pixel removal tools in MaxIM didn't do much at all. Instead I used the median kernel filter in MaxIM on each of my subframe right after initial reduction. I then did a median combine of the 8 subframes.
                                              The image is MUCH better! Take a look but please excuse my quick post-processing. Nothing was done to remove bad pixels in PS.
                                              http://publicmissiles.com/franku/2020_-25_f55_processed2_NGC_7331.jpg

                                              Of course, this is not a fix of the root cause but it's many times better than ever before. I'm still running my equipment tests.

                                              ---Frank Rocketman Uroda

                                              ----- Original Message -----
                                              From: Bert Katzung
                                              To: ccd-newastro@yahoogroups.com
                                              Sent: Sunday, October 01, 2006 11:52 AM
                                              Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop me!

                                              Hi Frank:
                                              I've had that sort of salt & pepper artifact problem on occasion with my
                                              ST10-XME; don't know what causes it or cures it, seems to have its own
                                              schedule.
                                              On the positive side, I find I can get rid of them with the hot and cold
                                              pixel removal tools in MaxIm. Extra steps, but they clean up pretty
                                              well---never have to use the clone tool in Photoshop.
                                              Bert

                                              katzung1@...
                                              www.astronomy-images.com
                                              www.visionlightgallery.com/katzung/

                                              ----- Original Message -----
                                              From: "Photon Collector" <photoncollector@...>
                                              To: <ccd-newastro@yahoogroups.com>
                                              Sent: Saturday, September 30, 2006 11:13 PM
                                              Subject: [ccd-newastro] I'm about to smash my ST2k........Please stop me!

                                              > People, I'm at wit's end.
                                              > I have been imaging with my ST2k imager for a couple years now. I have
                                              > always had big problems with random hot (or bright) pixels. My images and
                                              > darks have the usual consistent hot pixels that subtract out as they
                                              > should. But both the images and the darks also have a large quantity of
                                              > random hot pixels that differ from image to image and dark to dark. These
                                              > random hot pixels do not subtract out because they pop up at random
                                              > throughout the images and darks. The result is an image with many bright
                                              > and dark pixels. Bright pixels remain in the image because the dark frame
                                              > doesn't contain a corresponding bright pixel to subtract out. Dark pixels
                                              > appear in the reduced image because the dark frame has bright pixels where
                                              > there are none on the image.
                                              > To prove to myself that the problem is real, I subtracted one dark frame
                                              > from another dark frame shot in sequence. The resultant image should be
                                              > very smooth. Instead it has bright and dark pixels, just like my images.
                                              > As another test, I shot 10 darks in a row, of course all with the same
                                              > temp and time settings. Then I opened them up in both Maxim and CCDSoft
                                              > and ran a blink comparison. During the blink comparison, you can see that
                                              > about 1/2 of the hot pixels are fixed in their position while the rest
                                              > jump around all over the image. The same is true when doing a blink
                                              > comparison of a series of raw images shot in sequence.
                                              > I even went as far as upgrading my imaging chip from the older 2001 chip
                                              > to the new and (supposedly) less noisy 2020 chip at great cost to me. The
                                              > results are exactly the same.
                                              > Here is an example of a completed image:
                                              > http://publicmissiles.com/franku/2020_-25_f55_processed_NGC_7331.jpg
                                              > It is a combination of 8, 20 minute exposures median combined after
                                              > reduction using 10 median combined dark frames and the appropriate flat
                                              > fields.
                                              > If someone out there has a broadband connection (12 meg file!) and is
                                              > willing to help, I have up-loaded a zip file containing a raw image, a
                                              > flat field, and 3 dark frames. Try processing the image with the data I
                                              > provided to see if you can get a clean image......I sure can't. Here is
                                              > the zip file with everything you need:
                                              > http://publicmissiles.com/franku/Raw_stuff.zip
                                              > In the past I would spend an hour or two with the clone tool cleaning up
                                              > every bad pixel. But I just can't believe this is what everyone else goes
                                              > through. I never hear about problems similar to what I'm having. I hope
                                              > it's just something I'm doing wrong but I can't imagine what it is. Is it
                                              > possible that something in the observatory environment is causing the
                                              > random hot pixels?
                                              >
                                              >
                                              >
                                              > ---Frank Rocketman Uroda
                                              >

                                              [Non-text portions of this message have been removed]





                                              [Non-text portions of this message have been removed]
                                            • W. W. Mathis
                                              Hey Frank....... something that no one ever thinks about is to go down to the local Radio Shack store and buy some spray contact cleaner and use it liberally.
                                              Message 22 of 25 , Oct 2, 2006
                                                Hey Frank....... something that no one ever thinks about is to go down to the local Radio Shack store and buy some spray contact cleaner and use it liberally. They also have some other junk that you spray on the contacts to make them more conductive for electricity. Ward
                                                ----- Original Message -----
                                                From: Photon Collector
                                                To: ccd-newastro@yahoogroups.com
                                                Sent: Sunday, October 01, 2006 8:37 AM
                                                Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop me!


                                                I usually run CCDSoft and TheSky 6. I also control the laptop from the house using MS Remote Desktop via a network cable.
                                                I am running a series of tests now. I put the camera in a large cooler and wrapped the cooler with a heavy moving blanket. I also have the camera capped and set the Ha filter in place. Only CCDSoft is running. The dew heaters and mount drives are all off. Now I'm shooting a series of darks, three for each test.
                                                First test is with network cable unplugged.
                                                Next I will make a direct connection from the camera to the laptop via USB and bypass the hub.

                                                ---Frank Rocketman Uroda

                                                ----- Original Message -----
                                                From: Terry Platt
                                                To: ccd-newastro@yahoogroups.com
                                                Sent: Sunday, October 01, 2006 6:16 AM
                                                Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop me!

                                                Hi Frank,

                                                Random 'hot pixels' are usually data errors of some kind. For example, they could be due to interruptions of the camera download as other computer processes capture the bus. Is you control computer running free of other intensive applications? Network activity is a classic cause of random effects.

                                                Regards,
                                                Terry

                                                ----- Original Message -----
                                                From: Photon Collector
                                                To: ccd-newastro@yahoogroups.com
                                                Sent: Sunday, October 01, 2006 7:13 AM
                                                Subject: [ccd-newastro] I'm about to smash my ST2k........Please stop me!

                                                People, I'm at wit's end.
                                                I have been imaging with my ST2k imager for a couple years now. I have always had big problems with random hot (or bright) pixels. My images and darks have the usual consistent hot pixels that subtract out as they should. But both the images and the darks also have a large quantity of random hot pixels that differ from image to image and dark to dark. These random hot pixels do not subtract out because they pop up at random throughout the images and darks. The result is an image with many bright and dark pixels. Bright pixels remain in the image because the dark frame doesn't contain a corresponding bright pixel to subtract out. Dark pixels appear in the reduced image because the dark frame has bright pixels where there are none on the image.
                                                To prove to myself that the problem is real, I subtracted one dark frame from another dark frame shot in sequence. The resultant image should be very smooth. Instead it has bright and dark pixels, just like my images. As another test, I shot 10 darks in a row, of course all with the same temp and time settings. Then I opened them up in both Maxim and CCDSoft and ran a blink comparison. During the blink comparison, you can see that about 1/2 of the hot pixels are fixed in their position while the rest jump around all over the image. The same is true when doing a blink comparison of a series of raw images shot in sequence.
                                                I even went as far as upgrading my imaging chip from the older 2001 chip to the new and (supposedly) less noisy 2020 chip at great cost to me. The results are exactly the same.
                                                Here is an example of a completed image: http://publicmissiles.com/franku/2020_-25_f55_processed_NGC_7331.jpg
                                                It is a combination of 8, 20 minute exposures median combined after reduction using 10 median combined dark frames and the appropriate flat fields.
                                                If someone out there has a broadband connection (12 meg file!) and is willing to help, I have up-loaded a zip file containing a raw image, a flat field, and 3 dark frames. Try processing the image with the data I provided to see if you can get a clean image......I sure can't. Here is the zip file with everything you need: http://publicmissiles.com/franku/Raw_stuff.zip
                                                In the past I would spend an hour or two with the clone tool cleaning up every bad pixel. But I just can't believe this is what everyone else goes through. I never hear about problems similar to what I'm having. I hope it's just something I'm doing wrong but I can't imagine what it is. Is it possible that something in the observatory environment is causing the random hot pixels?

                                                ---Frank Rocketman Uroda

                                                [Non-text portions of this message have been removed]

                                                [Non-text portions of this message have been removed]

                                                [Non-text portions of this message have been removed]





                                                [Non-text portions of this message have been removed]
                                              • Wodaski - Yahoo
                                                That s not how CCD sensors actually work in the real world. Yes, you can have pixels that are routinely and regularly hot or cold. But you can also have pixels
                                                Message 23 of 25 , Oct 3, 2006
                                                  That's not how CCD sensors actually work in the real world. Yes, you can
                                                  have pixels that are routinely and regularly hot or cold. But you can
                                                  also have pixels that vary in how hot or cold they are. Your statement:

                                                  "Random pixels that pop up hot in one photo and then don't in another
                                                  photo can _only_ be due to random noise."

                                                  is just not true, and I want to correct the error before others start
                                                  assuming it is true. What is true is that the manufacturer must tune the
                                                  electronics for the camera to make sure that these variations are
                                                  minimized. The STL-11000 camera, for example, had a notorious problem
                                                  with these hot pixels until SBIG changed the camera driver to deal with
                                                  the problem. Even so, there is still a small population of these varying
                                                  pixels on most STL-11000 cameras, but the count is WAY down to a
                                                  reasonable number.

                                                  Such pixels are also going to occur on the ST-2000 series of cameras -
                                                  they seem to be harder to control in a certain generation of Kodak ABG
                                                  chips, but the camera drivers have all been revised to minimize this issue.

                                                  This isn't to say that there aren't other causes of random hot pixels,
                                                  and varying populations of hot pixels (such as the ones you cite). I
                                                  just want to be clear that there can be conditions other than readout
                                                  noise that determine this.

                                                  Ron

                                                  W. W. Mathis wrote:
                                                  > Frank: I've been thinking about your problem. I can see that a chip might have something wrong with a pixel that would give a "hot" pixel. But this hot pixel will be hot from now until doomsday, since it is an inherent defect in the chip. Random pixels that pop up hot in one photo and then don't in another photo can _only_ be due to random noise. So it seems to me that you should be looking for electrical problems that make the transmission "noisy". Poor connections, bad grounding, cross talk between wires, etc.
                                                  > . The computer will not accept info until it is ready to deal with it, so one program "Locking" another program out of memory really can't happen.
                                                  >
                                                  > Ward Mathis
                                                  > ----- Original Message -----
                                                  > From: Photon Collector
                                                  > To: ccd-newastro@yahoogroups.com
                                                  > Sent: Sunday, October 01, 2006 11:59 AM
                                                  > Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop me!
                                                  >
                                                  >
                                                  > The hot and cold pixel removal tools in MaxIM didn't do much at all. Instead I used the median kernel filter in MaxIM on each of my subframe right after initial reduction. I then did a median combine of the 8 subframes.
                                                  > The image is MUCH better! Take a look but please excuse my quick post-processing. Nothing was done to remove bad pixels in PS.
                                                  > http://publicmissiles.com/franku/2020_-25_f55_processed2_NGC_7331.jpg
                                                  >
                                                  > Of course, this is not a fix of the root cause but it's many times better than ever before. I'm still running my equipment tests.
                                                  >
                                                  > ---Frank Rocketman Uroda
                                                  >
                                                  > ----- Original Message -----
                                                  > From: Bert Katzung
                                                  > To: ccd-newastro@yahoogroups.com
                                                  > Sent: Sunday, October 01, 2006 11:52 AM
                                                  > Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop me!
                                                  >
                                                  > Hi Frank:
                                                  > I've had that sort of salt & pepper artifact problem on occasion with my
                                                  > ST10-XME; don't know what causes it or cures it, seems to have its own
                                                  > schedule.
                                                  > On the positive side, I find I can get rid of them with the hot and cold
                                                  > pixel removal tools in MaxIm. Extra steps, but they clean up pretty
                                                  > well---never have to use the clone tool in Photoshop.
                                                  > Bert
                                                  >
                                                  > katzung1@...
                                                  > www.astronomy-images.com
                                                  > www.visionlightgallery.com/katzung/
                                                  >
                                                  > ----- Original Message -----
                                                  > From: "Photon Collector" <photoncollector@...>
                                                  > To: <ccd-newastro@yahoogroups.com>
                                                  > Sent: Saturday, September 30, 2006 11:13 PM
                                                  > Subject: [ccd-newastro] I'm about to smash my ST2k........Please stop me!
                                                  >
                                                  > > People, I'm at wit's end.
                                                  > > I have been imaging with my ST2k imager for a couple years now. I have
                                                  > > always had big problems with random hot (or bright) pixels. My images and
                                                  > > darks have the usual consistent hot pixels that subtract out as they
                                                  > > should. But both the images and the darks also have a large quantity of
                                                  > > random hot pixels that differ from image to image and dark to dark. These
                                                  > > random hot pixels do not subtract out because they pop up at random
                                                  > > throughout the images and darks. The result is an image with many bright
                                                  > > and dark pixels. Bright pixels remain in the image because the dark frame
                                                  > > doesn't contain a corresponding bright pixel to subtract out. Dark pixels
                                                  > > appear in the reduced image because the dark frame has bright pixels where
                                                  > > there are none on the image.
                                                  > > To prove to myself that the problem is real, I subtracted one dark frame
                                                  > > from another dark frame shot in sequence. The resultant image should be
                                                  > > very smooth. Instead it has bright and dark pixels, just like my images.
                                                  > > As another test, I shot 10 darks in a row, of course all with the same
                                                  > > temp and time settings. Then I opened them up in both Maxim and CCDSoft
                                                  > > and ran a blink comparison. During the blink comparison, you can see that
                                                  > > about 1/2 of the hot pixels are fixed in their position while the rest
                                                  > > jump around all over the image. The same is true when doing a blink
                                                  > > comparison of a series of raw images shot in sequence.
                                                  > > I even went as far as upgrading my imaging chip from the older 2001 chip
                                                  > > to the new and (supposedly) less noisy 2020 chip at great cost to me. The
                                                  > > results are exactly the same.
                                                  > > Here is an example of a completed image:
                                                  > > http://publicmissiles.com/franku/2020_-25_f55_processed_NGC_7331.jpg
                                                  > > It is a combination of 8, 20 minute exposures median combined after
                                                  > > reduction using 10 median combined dark frames and the appropriate flat
                                                  > > fields.
                                                  > > If someone out there has a broadband connection (12 meg file!) and is
                                                  > > willing to help, I have up-loaded a zip file containing a raw image, a
                                                  > > flat field, and 3 dark frames. Try processing the image with the data I
                                                  > > provided to see if you can get a clean image......I sure can't. Here is
                                                  > > the zip file with everything you need:
                                                  > > http://publicmissiles.com/franku/Raw_stuff.zip
                                                  > > In the past I would spend an hour or two with the clone tool cleaning up
                                                  > > every bad pixel. But I just can't believe this is what everyone else goes
                                                  > > through. I never hear about problems similar to what I'm having. I hope
                                                  > > it's just something I'm doing wrong but I can't imagine what it is. Is it
                                                  > > possible that something in the observatory environment is causing the
                                                  > > random hot pixels?
                                                  > >
                                                  > >
                                                  > >
                                                  > > ---Frank Rocketman Uroda
                                                  > >
                                                  >
                                                  > [Non-text portions of this message have been removed]
                                                  >
                                                  >
                                                  >
                                                  >
                                                  >
                                                  > [Non-text portions of this message have been removed]
                                                  >
                                                  >
                                                  >
                                                  >
                                                  >
                                                  >
                                                  >
                                                  > Yahoo! Groups Links
                                                  >
                                                  >
                                                  >
                                                  >
                                                  >
                                                  >
                                                  >
                                                  >
                                                  >
                                                  >

                                                  --

                                                  Ron Wodaski
                                                  New Astronomy Press
                                                  http://www.newastro.com
                                                • W. W. Mathis
                                                  Ron: Thanks for setting that straight. I had forgetten that the signal from the pixel had to be digitized, and the signal (digital) that came across the
                                                  Message 24 of 25 , Oct 3, 2006
                                                    Ron: Thanks for setting that straight. I had forgetten that the signal from the pixel had to be digitized, and the signal (digital) that came across the wireing was a true reflection of the value of the pixel; and any corruption of this value would, of course, be due to noise. However this is an oversimplification of what goes on: the problem is with the analog signal that is given to digitizer. I was assuming that the analog signal was a reflection of how much light had fallen on the sensor. What you are saying is that this is not always the case.

                                                    I hope I didn't lead anyone astray. DON'T LISTEN TO ME, LISTEN TO RON-- HE IS THE EXPERT!

                                                    I have a question: why are the camera makers so uhhh "cagey" about the number of bad pixels on a chip: time after time I read "The rows of pixels contain no errors". This implys to me that the columns also contain no errors. Yet they are very careful not to say that. Do you know why?

                                                    Regards, Ward
                                                    ----- Original Message -----
                                                    From: Wodaski - Yahoo
                                                    To: ccd-newastro@yahoogroups.com
                                                    Sent: Tuesday, October 03, 2006 11:54 AM
                                                    Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop me!


                                                    That's not how CCD sensors actually work in the real world. Yes, you can
                                                    have pixels that are routinely and regularly hot or cold. But you can
                                                    also have pixels that vary in how hot or cold they are. Your statement:

                                                    "Random pixels that pop up hot in one photo and then don't in another
                                                    photo can _only_ be due to random noise."

                                                    is just not true, and I want to correct the error before others start
                                                    assuming it is true. What is true is that the manufacturer must tune the
                                                    electronics for the camera to make sure that these variations are
                                                    minimized. The STL-11000 camera, for example, had a notorious problem
                                                    with these hot pixels until SBIG changed the camera driver to deal with
                                                    the problem. Even so, there is still a small population of these varying
                                                    pixels on most STL-11000 cameras, but the count is WAY down to a
                                                    reasonable number.

                                                    Such pixels are also going to occur on the ST-2000 series of cameras -
                                                    they seem to be harder to control in a certain generation of Kodak ABG
                                                    chips, but the camera drivers have all been revised to minimize this issue.

                                                    This isn't to say that there aren't other causes of random hot pixels,
                                                    and varying populations of hot pixels (such as the ones you cite). I
                                                    just want to be clear that there can be conditions other than readout
                                                    noise that determine this.

                                                    Ron

                                                    W. W. Mathis wrote:
                                                    > Frank: I've been thinking about your problem. I can see that a chip might have something wrong with a pixel that would give a "hot" pixel. But this hot pixel will be hot from now until doomsday, since it is an inherent defect in the chip. Random pixels that pop up hot in one photo and then don't in another photo can _only_ be due to random noise. So it seems to me that you should be looking for electrical problems that make the transmission "noisy". Poor connections, bad grounding, cross talk between wires, etc.
                                                    > . The computer will not accept info until it is ready to deal with it, so one program "Locking" another program out of memory really can't happen.
                                                    >
                                                    > Ward Mathis
                                                    > ----- Original Message -----
                                                    > From: Photon Collector
                                                    > To: ccd-newastro@yahoogroups.com
                                                    > Sent: Sunday, October 01, 2006 11:59 AM
                                                    > Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop me!
                                                    >
                                                    >
                                                    > The hot and cold pixel removal tools in MaxIM didn't do much at all. Instead I used the median kernel filter in MaxIM on each of my subframe right after initial reduction. I then did a median combine of the 8 subframes.
                                                    > The image is MUCH better! Take a look but please excuse my quick post-processing. Nothing was done to remove bad pixels in PS.
                                                    > http://publicmissiles.com/franku/2020_-25_f55_processed2_NGC_7331.jpg
                                                    >
                                                    > Of course, this is not a fix of the root cause but it's many times better than ever before. I'm still running my equipment tests.
                                                    >
                                                    > ---Frank Rocketman Uroda
                                                    >
                                                    > ----- Original Message -----
                                                    > From: Bert Katzung
                                                    > To: ccd-newastro@yahoogroups.com
                                                    > Sent: Sunday, October 01, 2006 11:52 AM
                                                    > Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop me!
                                                    >
                                                    > Hi Frank:
                                                    > I've had that sort of salt & pepper artifact problem on occasion with my
                                                    > ST10-XME; don't know what causes it or cures it, seems to have its own
                                                    > schedule.
                                                    > On the positive side, I find I can get rid of them with the hot and cold
                                                    > pixel removal tools in MaxIm. Extra steps, but they clean up pretty
                                                    > well---never have to use the clone tool in Photoshop.
                                                    > Bert
                                                    >
                                                    > katzung1@...
                                                    > www.astronomy-images.com
                                                    > www.visionlightgallery.com/katzung/
                                                    >
                                                    > ----- Original Message -----
                                                    > From: "Photon Collector" <photoncollector@...>
                                                    > To: <ccd-newastro@yahoogroups.com>
                                                    > Sent: Saturday, September 30, 2006 11:13 PM
                                                    > Subject: [ccd-newastro] I'm about to smash my ST2k........Please stop me!
                                                    >
                                                    > > People, I'm at wit's end.
                                                    > > I have been imaging with my ST2k imager for a couple years now. I have
                                                    > > always had big problems with random hot (or bright) pixels. My images and
                                                    > > darks have the usual consistent hot pixels that subtract out as they
                                                    > > should. But both the images and the darks also have a large quantity of
                                                    > > random hot pixels that differ from image to image and dark to dark. These
                                                    > > random hot pixels do not subtract out because they pop up at random
                                                    > > throughout the images and darks. The result is an image with many bright
                                                    > > and dark pixels. Bright pixels remain in the image because the dark frame
                                                    > > doesn't contain a corresponding bright pixel to subtract out. Dark pixels
                                                    > > appear in the reduced image because the dark frame has bright pixels where
                                                    > > there are none on the image.
                                                    > > To prove to myself that the problem is real, I subtracted one dark frame
                                                    > > from another dark frame shot in sequence. The resultant image should be
                                                    > > very smooth. Instead it has bright and dark pixels, just like my images.
                                                    > > As another test, I shot 10 darks in a row, of course all with the same
                                                    > > temp and time settings. Then I opened them up in both Maxim and CCDSoft
                                                    > > and ran a blink comparison. During the blink comparison, you can see that
                                                    > > about 1/2 of the hot pixels are fixed in their position while the rest
                                                    > > jump around all over the image. The same is true when doing a blink
                                                    > > comparison of a series of raw images shot in sequence.
                                                    > > I even went as far as upgrading my imaging chip from the older 2001 chip
                                                    > > to the new and (supposedly) less noisy 2020 chip at great cost to me. The
                                                    > > results are exactly the same.
                                                    > > Here is an example of a completed image:
                                                    > > http://publicmissiles.com/franku/2020_-25_f55_processed_NGC_7331.jpg
                                                    > > It is a combination of 8, 20 minute exposures median combined after
                                                    > > reduction using 10 median combined dark frames and the appropriate flat
                                                    > > fields.
                                                    > > If someone out there has a broadband connection (12 meg file!) and is
                                                    > > willing to help, I have up-loaded a zip file containing a raw image, a
                                                    > > flat field, and 3 dark frames. Try processing the image with the data I
                                                    > > provided to see if you can get a clean image......I sure can't. Here is
                                                    > > the zip file with everything you need:
                                                    > > http://publicmissiles.com/franku/Raw_stuff.zip
                                                    > > In the past I would spend an hour or two with the clone tool cleaning up
                                                    > > every bad pixel. But I just can't believe this is what everyone else goes
                                                    > > through. I never hear about problems similar to what I'm having. I hope
                                                    > > it's just something I'm doing wrong but I can't imagine what it is. Is it
                                                    > > possible that something in the observatory environment is causing the
                                                    > > random hot pixels?
                                                    > >
                                                    > >
                                                    > >
                                                    > > ---Frank Rocketman Uroda
                                                    > >
                                                    >
                                                    > [Non-text portions of this message have been removed]
                                                    >
                                                    >
                                                    >
                                                    >
                                                    >
                                                    > [Non-text portions of this message have been removed]
                                                    >
                                                    >
                                                    >
                                                    >
                                                    >
                                                    >
                                                    >
                                                    > Yahoo! Groups Links
                                                    >
                                                    >
                                                    >
                                                    >
                                                    >
                                                    >
                                                    >
                                                    >
                                                    >
                                                    >

                                                    --

                                                    Ron Wodaski
                                                    New Astronomy Press
                                                    http://www.newastro.com





                                                    [Non-text portions of this message have been removed]
                                                  • Wodaski - Yahoo
                                                    That s correct - the chip/electronics can be responsible for hot pixels. The camera designers try to optimize the camera electronics to minimize this. I hadn t
                                                    Message 25 of 25 , Oct 4, 2006
                                                      That's correct - the chip/electronics can be responsible for hot pixels.
                                                      The camera designers try to optimize the camera electronics to minimize
                                                      this.

                                                      I hadn't seen the language you mention.

                                                      Ron

                                                      W. W. Mathis wrote:
                                                      > Ron: Thanks for setting that straight. I had forgetten that the signal from the pixel had to be digitized, and the signal (digital) that came across the wireing was a true reflection of the value of the pixel; and any corruption of this value would, of course, be due to noise. However this is an oversimplification of what goes on: the problem is with the analog signal that is given to digitizer. I was assuming that the analog signal was a reflection of how much light had fallen on the sensor. What you are saying is that this is not always the case.
                                                      >
                                                      > I hope I didn't lead anyone astray. DON'T LISTEN TO ME, LISTEN TO RON-- HE IS THE EXPERT!
                                                      >
                                                      > I have a question: why are the camera makers so uhhh "cagey" about the number of bad pixels on a chip: time after time I read "The rows of pixels contain no errors". This implys to me that the columns also contain no errors. Yet they are very careful not to say that. Do you know why?
                                                      >
                                                      > Regards, Ward
                                                      > ----- Original Message -----
                                                      > From: Wodaski - Yahoo
                                                      > To: ccd-newastro@yahoogroups.com
                                                      > Sent: Tuesday, October 03, 2006 11:54 AM
                                                      > Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop me!
                                                      >
                                                      >
                                                      > That's not how CCD sensors actually work in the real world. Yes, you can
                                                      > have pixels that are routinely and regularly hot or cold. But you can
                                                      > also have pixels that vary in how hot or cold they are. Your statement:
                                                      >
                                                      > "Random pixels that pop up hot in one photo and then don't in another
                                                      > photo can _only_ be due to random noise."
                                                      >
                                                      > is just not true, and I want to correct the error before others start
                                                      > assuming it is true. What is true is that the manufacturer must tune the
                                                      > electronics for the camera to make sure that these variations are
                                                      > minimized. The STL-11000 camera, for example, had a notorious problem
                                                      > with these hot pixels until SBIG changed the camera driver to deal with
                                                      > the problem. Even so, there is still a small population of these varying
                                                      > pixels on most STL-11000 cameras, but the count is WAY down to a
                                                      > reasonable number.
                                                      >
                                                      > Such pixels are also going to occur on the ST-2000 series of cameras -
                                                      > they seem to be harder to control in a certain generation of Kodak ABG
                                                      > chips, but the camera drivers have all been revised to minimize this issue.
                                                      >
                                                      > This isn't to say that there aren't other causes of random hot pixels,
                                                      > and varying populations of hot pixels (such as the ones you cite). I
                                                      > just want to be clear that there can be conditions other than readout
                                                      > noise that determine this.
                                                      >
                                                      > Ron
                                                      >
                                                      > W. W. Mathis wrote:
                                                      > > Frank: I've been thinking about your problem. I can see that a chip might have something wrong with a pixel that would give a "hot" pixel. But this hot pixel will be hot from now until doomsday, since it is an inherent defect in the chip. Random pixels that pop up hot in one photo and then don't in another photo can _only_ be due to random noise. So it seems to me that you should be looking for electrical problems that make the transmission "noisy". Poor connections, bad grounding, cross talk between wires, etc.
                                                      > > . The computer will not accept info until it is ready to deal with it, so one program "Locking" another program out of memory really can't happen.
                                                      > >
                                                      > > Ward Mathis
                                                      > > ----- Original Message -----
                                                      > > From: Photon Collector
                                                      > > To: ccd-newastro@yahoogroups.com
                                                      > > Sent: Sunday, October 01, 2006 11:59 AM
                                                      > > Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop me!
                                                      > >
                                                      > >
                                                      > > The hot and cold pixel removal tools in MaxIM didn't do much at all. Instead I used the median kernel filter in MaxIM on each of my subframe right after initial reduction. I then did a median combine of the 8 subframes.
                                                      > > The image is MUCH better! Take a look but please excuse my quick post-processing. Nothing was done to remove bad pixels in PS.
                                                      > > http://publicmissiles.com/franku/2020_-25_f55_processed2_NGC_7331.jpg
                                                      > >
                                                      > > Of course, this is not a fix of the root cause but it's many times better than ever before. I'm still running my equipment tests.
                                                      > >
                                                      > > ---Frank Rocketman Uroda
                                                      > >
                                                      > > ----- Original Message -----
                                                      > > From: Bert Katzung
                                                      > > To: ccd-newastro@yahoogroups.com
                                                      > > Sent: Sunday, October 01, 2006 11:52 AM
                                                      > > Subject: Re: [ccd-newastro] I'm about to smash my ST2k........Please stop me!
                                                      > >
                                                      > > Hi Frank:
                                                      > > I've had that sort of salt & pepper artifact problem on occasion with my
                                                      > > ST10-XME; don't know what causes it or cures it, seems to have its own
                                                      > > schedule.
                                                      > > On the positive side, I find I can get rid of them with the hot and cold
                                                      > > pixel removal tools in MaxIm. Extra steps, but they clean up pretty
                                                      > > well---never have to use the clone tool in Photoshop.
                                                      > > Bert
                                                      > >
                                                      > > katzung1@...
                                                      > > www.astronomy-images.com
                                                      > > www.visionlightgallery.com/katzung/
                                                      > >
                                                      > > ----- Original Message -----
                                                      > > From: "Photon Collector" <photoncollector@...>
                                                      > > To: <ccd-newastro@yahoogroups.com>
                                                      > > Sent: Saturday, September 30, 2006 11:13 PM
                                                      > > Subject: [ccd-newastro] I'm about to smash my ST2k........Please stop me!
                                                      > >
                                                      > > > People, I'm at wit's end.
                                                      > > > I have been imaging with my ST2k imager for a couple years now. I have
                                                      > > > always had big problems with random hot (or bright) pixels. My images and
                                                      > > > darks have the usual consistent hot pixels that subtract out as they
                                                      > > > should. But both the images and the darks also have a large quantity of
                                                      > > > random hot pixels that differ from image to image and dark to dark. These
                                                      > > > random hot pixels do not subtract out because they pop up at random
                                                      > > > throughout the images and darks. The result is an image with many bright
                                                      > > > and dark pixels. Bright pixels remain in the image because the dark frame
                                                      > > > doesn't contain a corresponding bright pixel to subtract out. Dark pixels
                                                      > > > appear in the reduced image because the dark frame has bright pixels where
                                                      > > > there are none on the image.
                                                      > > > To prove to myself that the problem is real, I subtracted one dark frame
                                                      > > > from another dark frame shot in sequence. The resultant image should be
                                                      > > > very smooth. Instead it has bright and dark pixels, just like my images.
                                                      > > > As another test, I shot 10 darks in a row, of course all with the same
                                                      > > > temp and time settings. Then I opened them up in both Maxim and CCDSoft
                                                      > > > and ran a blink comparison. During the blink comparison, you can see that
                                                      > > > about 1/2 of the hot pixels are fixed in their position while the rest
                                                      > > > jump around all over the image. The same is true when doing a blink
                                                      > > > comparison of a series of raw images shot in sequence.
                                                      > > > I even went as far as upgrading my imaging chip from the older 2001 chip
                                                      > > > to the new and (supposedly) less noisy 2020 chip at great cost to me. The
                                                      > > > results are exactly the same.
                                                      > > > Here is an example of a completed image:
                                                      > > > http://publicmissiles.com/franku/2020_-25_f55_processed_NGC_7331.jpg
                                                      > > > It is a combination of 8, 20 minute exposures median combined after
                                                      > > > reduction using 10 median combined dark frames and the appropriate flat
                                                      > > > fields.
                                                      > > > If someone out there has a broadband connection (12 meg file!) and is
                                                      > > > willing to help, I have up-loaded a zip file containing a raw image, a
                                                      > > > flat field, and 3 dark frames. Try processing the image with the data I
                                                      > > > provided to see if you can get a clean image......I sure can't. Here is
                                                      > > > the zip file with everything you need:
                                                      > > > http://publicmissiles.com/franku/Raw_stuff.zip
                                                      > > > In the past I would spend an hour or two with the clone tool cleaning up
                                                      > > > every bad pixel. But I just can't believe this is what everyone else goes
                                                      > > > through. I never hear about problems similar to what I'm having. I hope
                                                      > > > it's just something I'm doing wrong but I can't imagine what it is. Is it
                                                      > > > possible that something in the observatory environment is causing the
                                                      > > > random hot pixels?
                                                      > > >
                                                      > > >
                                                      > > >
                                                      > > > ---Frank Rocketman Uroda
                                                      > > >
                                                      > >
                                                      > > [Non-text portions of this message have been removed]
                                                      > >
                                                      > >
                                                      > >
                                                      > >
                                                      > >
                                                      > > [Non-text portions of this message have been removed]
                                                      > >
                                                      > >
                                                      > >
                                                      > >
                                                      > >
                                                      > >
                                                      > >
                                                      > > Yahoo! Groups Links
                                                      > >
                                                      > >
                                                      > >
                                                      > >
                                                      > >
                                                      > >
                                                      > >
                                                      > >
                                                      > >
                                                      > >
                                                      >
                                                      > --
                                                      >
                                                      > Ron Wodaski
                                                      > New Astronomy Press
                                                      > http://www.newastro.com
                                                      >
                                                      >
                                                      >
                                                      >
                                                      >
                                                      > [Non-text portions of this message have been removed]
                                                      >
                                                      >
                                                      >
                                                      >
                                                      >
                                                      >
                                                      > Yahoo! Groups Links
                                                      >
                                                      >
                                                      >
                                                      >
                                                      >
                                                      >
                                                      >
                                                      >
                                                      >
                                                      >

                                                      --

                                                      Ron Wodaski
                                                      New Astronomy Press
                                                      http://www.newastro.com
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