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54550Re: [ccd-newastro] I'm about to smash my ST2k........Please stop me!

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  • Photon Collector
    Oct 1, 2006
    • 0 Attachment
      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

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