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Camera test report

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  • Wodaski - Yahoo
    Bob Holzer sent me his SXV-H9 camera for some testing recently. I ve been imaging with it on the Tak Sky90 (with f/4.5 reducer). The small pixels of this
    Message 1 of 6 , Jan 2, 2004
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      Bob Holzer sent me his SXV-H9 camera for some testing recently. I've been
      imaging with it on the Tak Sky90 (with f/4.5 reducer). The small pixels of
      this camera have been handy with such a short focal length (400mm). Image
      quality is very good, as you can see from the images I've been taking over
      the last few days:

      http://www.blackbird-observatory.com/img/Sky90/SXV-H9/

      A few notes on some of the images:

      * The Horsehead image was taken with the camera newly inserted into the
      scope, and I think the camera was still warmer than the scope. This led to
      some elongation that looks like coma; it went away when the temperatures
      equalized.

      * The color in one of the Sculptor Galaxy images is from an ST-1001E image.

      * Most images were taken with 5-minute sub exposures. The Sculptor images
      were 10-minute sub exposures.

      * The Struve image was a test to see if a very dim nebula could be detected
      OK; it was - the nebula really is that dim. <g>

      The camera was easy to use, although it took a while to find and then figure
      out how to install the software update (no readme). That's about the only
      negative. No darks were used. Camera temperature was a chilly 10-15 degrees
      for most of these images; I would be curious to see how it performs
      noise-wise in the summer time with higher ambient temperatures.


      Ron Wodaski
      The New CCD Astronomy Book
      web site: http://www.newastro.com
    • Rick Krejci
      Glad you liked it, Ron. You certainly got quite a bit of production out of it! As far as higher temps, I use mine in about the hottest area you ll get, with
      Message 2 of 6 , Jan 2, 2004
      • 0 Attachment
        Glad you liked it, Ron. You certainly got quite a bit of production
        out of it!

        As far as higher temps, I use mine in about the hottest area you'll
        get, with summertime overnight temps staying in the 90's. I still
        had no need for darks, just relying on Maxim's hot pixel remover.
        There certainly was more hot pixels, but no more low-level noise than
        when it's cold. And it's the lack of the low-level noise that shows
        up in the dimmest backgrounds when stretched...I don't get that
        streaking effect when there is frame to frame drift.

        Rick

        --- In ccd-newastro@yahoogroups.com, "Wodaski - Yahoo" <yahoo@w...>
        wrote:
        > Bob Holzer sent me his SXV-H9 camera for some testing recently.
        I've been
        > imaging with it on the Tak Sky90 (with f/4.5 reducer). The small
        pixels of
        > this camera have been handy with such a short focal length (400mm).
        Image
        > quality is very good, as you can see from the images I've been
        taking over
        > the last few days:
        >
        > http://www.blackbird-observatory.com/img/Sky90/SXV-H9/
        >
        > A few notes on some of the images:
        >
        > * The Horsehead image was taken with the camera newly inserted into
        the
        > scope, and I think the camera was still warmer than the scope. This
        led to
        > some elongation that looks like coma; it went away when the
        temperatures
        > equalized.
        >
        > * The color in one of the Sculptor Galaxy images is from an ST-
        1001E image.
        >
        > * Most images were taken with 5-minute sub exposures. The Sculptor
        images
        > were 10-minute sub exposures.
        >
        > * The Struve image was a test to see if a very dim nebula could be
        detected
        > OK; it was - the nebula really is that dim. <g>
        >
        > The camera was easy to use, although it took a while to find and
        then figure
        > out how to install the software update (no readme). That's about
        the only
        > negative. No darks were used. Camera temperature was a chilly 10-15
        degrees
        > for most of these images; I would be curious to see how it performs
        > noise-wise in the summer time with higher ambient temperatures.
        >
        >
        > Ron Wodaski
        > The New CCD Astronomy Book
        > web site: http://www.newastro.com
      • Wodaski - Yahoo
        What is the difference between summer and winter background standard deviation on equal exposure times? I can t reconcile no need for darks with more hot
        Message 3 of 6 , Jan 2, 2004
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          What is the difference between summer and winter background standard
          deviation on equal exposure times? I can't reconcile "no need for darks"
          with "more hot pixels." I'd like to get a handle on the actual values, as I
          don't think Bob will let me keep the camera for 6 months. <g> To me, hot
          pixels are just the obvious harbingers of less noticeable noise, which a
          dark controls. Maybe one should be using darks in the summer, but only a
          numerical analysis would demonstrate that, or not.

          If you are getting streaking from a full-frame chip, then it's more likely
          an issue of technique. Properly done, there will be no streaking (multiple
          darks, sufficient exposure times). The unvarnished truth would be that you
          can get that result without darks using the SXV-H9, though of course at a
          cost in sensitivity, so even though you don't need to take darks, any time
          savings are reduced or eliminated. It becomes a matter of price, software,
          support, documentation, and of course buyer preference as to which type of
          camera to buy. The important things from the buyer's perspective is that
          this camera is a useful tool. I used it with MaxIm DL, which I would
          strongly recommend.

          What is important to note is that the chip in this camera is an advance over
          previous generations of the Sony chips, and the image quality is improved. I
          wouldn't be surprised to see other vendors rallying around the chip, though
          I know of no plans to do so. I certainly enjoyed using the chip, but I'm
          going to go back to the ST-10XME as my regular camera. <g>


          Ron Wodaski
          The New CCD Astronomy Book
          web site: http://www.newastro.com


          -----Original Message-----
          From: Rick Krejci [mailto:randckrejci@...]
          Sent: Friday, January 02, 2004 8:52 AM
          To: ccd-newastro@yahoogroups.com
          Subject: [ccd-newastro] Re: Camera test report

          Glad you liked it, Ron. You certainly got quite a bit of production
          out of it!

          As far as higher temps, I use mine in about the hottest area you'll
          get, with summertime overnight temps staying in the 90's. I still
          had no need for darks, just relying on Maxim's hot pixel remover.
          There certainly was more hot pixels, but no more low-level noise than
          when it's cold. And it's the lack of the low-level noise that shows
          up in the dimmest backgrounds when stretched...I don't get that
          streaking effect when there is frame to frame drift.

          Rick

          --- In ccd-newastro@yahoogroups.com, "Wodaski - Yahoo" <yahoo@w...>
          wrote:
          > Bob Holzer sent me his SXV-H9 camera for some testing recently.
          I've been
          > imaging with it on the Tak Sky90 (with f/4.5 reducer). The small
          pixels of
          > this camera have been handy with such a short focal length (400mm).
          Image
          > quality is very good, as you can see from the images I've been
          taking over
          > the last few days:
          >
          > http://www.blackbird-observatory.com/img/Sky90/SXV-H9/
          >
          > A few notes on some of the images:
          >
          > * The Horsehead image was taken with the camera newly inserted into
          the
          > scope, and I think the camera was still warmer than the scope. This
          led to
          > some elongation that looks like coma; it went away when the
          temperatures
          > equalized.
          >
          > * The color in one of the Sculptor Galaxy images is from an ST-
          1001E image.
          >
          > * Most images were taken with 5-minute sub exposures. The Sculptor
          images
          > were 10-minute sub exposures.
          >
          > * The Struve image was a test to see if a very dim nebula could be
          detected
          > OK; it was - the nebula really is that dim. <g>
          >
          > The camera was easy to use, although it took a while to find and
          then figure
          > out how to install the software update (no readme). That's about
          the only
          > negative. No darks were used. Camera temperature was a chilly 10-15
          degrees
          > for most of these images; I would be curious to see how it performs
          > noise-wise in the summer time with higher ambient temperatures.
          >
          >
          > Ron Wodaski
          > The New CCD Astronomy Book
          > web site: http://www.newastro.com




          Yahoo! Groups Links

          To visit your group on the web, go to:
          http://groups.yahoo.com/group/ccd-newastro/

          To unsubscribe from this group, send an email to:
          ccd-newastro-unsubscribe@yahoogroups.com

          Your use of Yahoo! Groups is subject to:
          http://docs.yahoo.com/info/terms/
        • Rick Krejci
          Streaking is a -very- common issue with beginners and is an indication of improperly dark corrected image, whether it be from using only a single dark with a
          Message 4 of 6 , Jan 2, 2004
          • 0 Attachment
            Streaking is a -very- common issue with beginners and is an
            indication of improperly dark corrected image, whether it be from
            using only a single dark with a series of lights or from using old
            darks. It can certainly happen in all manufacturers cameras and is
            certainly avoidable with good technique.

            And, in most cameras, you are correct that hot pixels are harbingers
            of other noise. My very point was that this is not the case with the
            SXV...the fact that there is no noticeable streaking pattern
            discernable after removing the hot pixels indicates to me that any
            remaining noise is well below the sky background, even for short Ha
            exposures.

            Rick



            --- In ccd-newastro@yahoogroups.com, "Wodaski - Yahoo" <yahoo@w...>
            wrote:
            > What is the difference between summer and winter background standard
            > deviation on equal exposure times? I can't reconcile "no need for
            darks"
            > with "more hot pixels." I'd like to get a handle on the actual
            values, as I
            > don't think Bob will let me keep the camera for 6 months. <g> To
            me, hot
            > pixels are just the obvious harbingers of less noticeable noise,
            which a
            > dark controls. Maybe one should be using darks in the summer, but
            only a
            > numerical analysis would demonstrate that, or not.
            >
            > If you are getting streaking from a full-frame chip, then it's more
            likely
            > an issue of technique. Properly done, there will be no streaking
            (multiple
            > darks, sufficient exposure times). The unvarnished truth would be
            that you
            > can get that result without darks using the SXV-H9, though of
            course at a
            > cost in sensitivity, so even though you don't need to take darks,
            any time
            > savings are reduced or eliminated. It becomes a matter of price,
            software,
            > support, documentation, and of course buyer preference as to which
            type of
            > camera to buy. The important things from the buyer's perspective is
            that
            > this camera is a useful tool. I used it with MaxIm DL, which I would
            > strongly recommend.
            >
            > What is important to note is that the chip in this camera is an
            advance over
            > previous generations of the Sony chips, and the image quality is
            improved. I
            > wouldn't be surprised to see other vendors rallying around the
            chip, though
            > I know of no plans to do so. I certainly enjoyed using the chip,
            but I'm
            > going to go back to the ST-10XME as my regular camera. <g>
            >
            >
            > Ron Wodaski
            > The New CCD Astronomy Book
            > web site: http://www.newastro.com
            >
            >
            > -----Original Message-----
            > From: Rick Krejci [mailto:randckrejci@y...]
            > Sent: Friday, January 02, 2004 8:52 AM
            > To: ccd-newastro@yahoogroups.com
            > Subject: [ccd-newastro] Re: Camera test report
            >
            > Glad you liked it, Ron. You certainly got quite a bit of
            production
            > out of it!
            >
            > As far as higher temps, I use mine in about the hottest area you'll
            > get, with summertime overnight temps staying in the 90's. I still
            > had no need for darks, just relying on Maxim's hot pixel remover.
            > There certainly was more hot pixels, but no more low-level noise
            than
            > when it's cold. And it's the lack of the low-level noise that
            shows
            > up in the dimmest backgrounds when stretched...I don't get that
            > streaking effect when there is frame to frame drift.
            >
            > Rick
            >
            > --- In ccd-newastro@yahoogroups.com, "Wodaski - Yahoo" <yahoo@w...>
            > wrote:
            > > Bob Holzer sent me his SXV-H9 camera for some testing recently.
            > I've been
            > > imaging with it on the Tak Sky90 (with f/4.5 reducer). The small
            > pixels of
            > > this camera have been handy with such a short focal length
            (400mm).
            > Image
            > > quality is very good, as you can see from the images I've been
            > taking over
            > > the last few days:
            > >
            > > http://www.blackbird-observatory.com/img/Sky90/SXV-H9/
            > >
            > > A few notes on some of the images:
            > >
            > > * The Horsehead image was taken with the camera newly inserted
            into
            > the
            > > scope, and I think the camera was still warmer than the scope.
            This
            > led to
            > > some elongation that looks like coma; it went away when the
            > temperatures
            > > equalized.
            > >
            > > * The color in one of the Sculptor Galaxy images is from an ST-
            > 1001E image.
            > >
            > > * Most images were taken with 5-minute sub exposures. The
            Sculptor
            > images
            > > were 10-minute sub exposures.
            > >
            > > * The Struve image was a test to see if a very dim nebula could
            be
            > detected
            > > OK; it was - the nebula really is that dim. <g>
            > >
            > > The camera was easy to use, although it took a while to find and
            > then figure
            > > out how to install the software update (no readme). That's about
            > the only
            > > negative. No darks were used. Camera temperature was a chilly 10-
            15
            > degrees
            > > for most of these images; I would be curious to see how it
            performs
            > > noise-wise in the summer time with higher ambient temperatures.
            > >
            > >
            > > Ron Wodaski
            > > The New CCD Astronomy Book
            > > web site: http://www.newastro.com
            >
            >
            >
            >
            > Yahoo! Groups Links
            >
            > To visit your group on the web, go to:
            > http://groups.yahoo.com/group/ccd-newastro/
            >
            > To unsubscribe from this group, send an email to:
            > ccd-newastro-unsubscribe@yahoogroups.com
            >
            > Your use of Yahoo! Groups is subject to:
            > http://docs.yahoo.com/info/terms/
          • Wodaski - Yahoo
            I think you misunderstand. There would be no streaking from noisy pixels that are below the visible threshold, just loss of clarity due to noise (which,
            Message 5 of 6 , Jan 2, 2004
            • 0 Attachment
              I think you misunderstand. There would be no streaking from noisy pixels
              that are below the visible threshold, just loss of clarity due to noise
              (which, remember, is uncertainly in the brightness values of the signal). A
              larger uncertainty in values is a hot pixel that you can see with the eye; a
              smaller uncertainty in values simply robs the image of details by varying
              the brightness values. If the eye spots hot pixels, then in my experience
              the smaller noise is also present. But the smaller noise isn't necessarily
              visible, even though it will have visible effects. It is much easier to
              visualize the presence of something (a hot pixel) than an absence (details
              that would have been there but for the noise). Thus a visual inspection by
              its very nature is never rigorous enough to prove this point.

              All I'm asking is that you measure the noise instead of characterizing it by
              eye - smaller noise levels are harder to judge, since the only evidence is
              missing detail, which is hard to characterize. Measurements of standard
              deviation are much more useful for making comparisons. I can't accept "no
              noticeable" since the type of noise I'm talking about doesn't have
              noticeable as a characteristic. <g> As with most noise, it is simply masking
              signal, an effect that is impossible to measure directly. Std. Deviation is
              a good correlation for most purposes, however, thus my request.

              What you would do is take equal exposure times winter and summer, and
              measure the std. dev. of a background area with similar brightness levels.
              This might require taking samples across a number of nights in the winter,
              and a number of nights in the summer, so that you can find a reasonable
              match. It would be interesting to do this again after a hot pixel removal;
              that would go some way toward proving or disproving your hypothesis.

              Until then, motion denied. <g> Next case.

              Ron Wodaski
              The New CCD Astronomy Book
              web site: http://www.newastro.com


              -----Original Message-----
              From: Rick Krejci [mailto:randckrejci@...]
              Sent: Friday, January 02, 2004 1:50 PM
              To: ccd-newastro@yahoogroups.com
              Subject: [ccd-newastro] Re: Camera test report

              Streaking is a -very- common issue with beginners and is an
              indication of improperly dark corrected image, whether it be from
              using only a single dark with a series of lights or from using old
              darks. It can certainly happen in all manufacturers cameras and is
              certainly avoidable with good technique.

              And, in most cameras, you are correct that hot pixels are harbingers
              of other noise. My very point was that this is not the case with the
              SXV...the fact that there is no noticeable streaking pattern
              discernable after removing the hot pixels indicates to me that any
              remaining noise is well below the sky background, even for short Ha
              exposures.

              Rick



              --- In ccd-newastro@yahoogroups.com, "Wodaski - Yahoo" <yahoo@w...>
              wrote:
              > What is the difference between summer and winter background standard
              > deviation on equal exposure times? I can't reconcile "no need for
              darks"
              > with "more hot pixels." I'd like to get a handle on the actual
              values, as I
              > don't think Bob will let me keep the camera for 6 months. <g> To
              me, hot
              > pixels are just the obvious harbingers of less noticeable noise,
              which a
              > dark controls. Maybe one should be using darks in the summer, but
              only a
              > numerical analysis would demonstrate that, or not.
              >
              > If you are getting streaking from a full-frame chip, then it's more
              likely
              > an issue of technique. Properly done, there will be no streaking
              (multiple
              > darks, sufficient exposure times). The unvarnished truth would be
              that you
              > can get that result without darks using the SXV-H9, though of
              course at a
              > cost in sensitivity, so even though you don't need to take darks,
              any time
              > savings are reduced or eliminated. It becomes a matter of price,
              software,
              > support, documentation, and of course buyer preference as to which
              type of
              > camera to buy. The important things from the buyer's perspective is
              that
              > this camera is a useful tool. I used it with MaxIm DL, which I would
              > strongly recommend.
              >
              > What is important to note is that the chip in this camera is an
              advance over
              > previous generations of the Sony chips, and the image quality is
              improved. I
              > wouldn't be surprised to see other vendors rallying around the
              chip, though
              > I know of no plans to do so. I certainly enjoyed using the chip,
              but I'm
              > going to go back to the ST-10XME as my regular camera. <g>
              >
              >
              > Ron Wodaski
              > The New CCD Astronomy Book
              > web site: http://www.newastro.com
              >
              >
              > -----Original Message-----
              > From: Rick Krejci [mailto:randckrejci@y...]
              > Sent: Friday, January 02, 2004 8:52 AM
              > To: ccd-newastro@yahoogroups.com
              > Subject: [ccd-newastro] Re: Camera test report
              >
              > Glad you liked it, Ron. You certainly got quite a bit of
              production
              > out of it!
              >
              > As far as higher temps, I use mine in about the hottest area you'll
              > get, with summertime overnight temps staying in the 90's. I still
              > had no need for darks, just relying on Maxim's hot pixel remover.
              > There certainly was more hot pixels, but no more low-level noise
              than
              > when it's cold. And it's the lack of the low-level noise that
              shows
              > up in the dimmest backgrounds when stretched...I don't get that
              > streaking effect when there is frame to frame drift.
              >
              > Rick
              >
              > --- In ccd-newastro@yahoogroups.com, "Wodaski - Yahoo" <yahoo@w...>
              > wrote:
              > > Bob Holzer sent me his SXV-H9 camera for some testing recently.
              > I've been
              > > imaging with it on the Tak Sky90 (with f/4.5 reducer). The small
              > pixels of
              > > this camera have been handy with such a short focal length
              (400mm).
              > Image
              > > quality is very good, as you can see from the images I've been
              > taking over
              > > the last few days:
              > >
              > > http://www.blackbird-observatory.com/img/Sky90/SXV-H9/
              > >
              > > A few notes on some of the images:
              > >
              > > * The Horsehead image was taken with the camera newly inserted
              into
              > the
              > > scope, and I think the camera was still warmer than the scope.
              This
              > led to
              > > some elongation that looks like coma; it went away when the
              > temperatures
              > > equalized.
              > >
              > > * The color in one of the Sculptor Galaxy images is from an ST-
              > 1001E image.
              > >
              > > * Most images were taken with 5-minute sub exposures. The
              Sculptor
              > images
              > > were 10-minute sub exposures.
              > >
              > > * The Struve image was a test to see if a very dim nebula could
              be
              > detected
              > > OK; it was - the nebula really is that dim. <g>
              > >
              > > The camera was easy to use, although it took a while to find and
              > then figure
              > > out how to install the software update (no readme). That's about
              > the only
              > > negative. No darks were used. Camera temperature was a chilly 10-
              15
              > degrees
              > > for most of these images; I would be curious to see how it
              performs
              > > noise-wise in the summer time with higher ambient temperatures.
              > >
              > >
              > > Ron Wodaski
              > > The New CCD Astronomy Book
              > > web site: http://www.newastro.com
              >
              >
              >
              >
              > Yahoo! Groups Links
              >
              > To visit your group on the web, go to:
              > http://groups.yahoo.com/group/ccd-newastro/
              >
              > To unsubscribe from this group, send an email to:
              > ccd-newastro-unsubscribe@yahoogroups.com
              >
              > Your use of Yahoo! Groups is subject to:
              > http://docs.yahoo.com/info/terms/




              Yahoo! Groups Links

              To visit your group on the web, go to:
              http://groups.yahoo.com/group/ccd-newastro/

              To unsubscribe from this group, send an email to:
              ccd-newastro-unsubscribe@yahoogroups.com

              Your use of Yahoo! Groups is subject to:
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            • Rick Krejci
              I understand what you are saying. But I don t have the direct evidence you need, so I was trying to help you out by relating my direct experience which is the
              Message 6 of 6 , Jan 2, 2004
              • 0 Attachment
                I understand what you are saying. But I don't have the direct
                evidence you need, so I was trying to help you out by relating my
                direct experience which is the best anyone can do. Most SXV users
                don't have dark libraries hanging around to compare, since they are
                not needed. And you really can't compare similar DSO shots from
                different seasons due to the innumerable other variables.

                And, really, I'm not into the theory as much the practice and
                results. My best example I have of extreme summertime imaging would
                be this Ha Pelican image taken last July with 48 2 minute
                subexposures and no darks at about 95F average ambient:

                http://www.ricksastro.com/Gallery/pelicanha.jpg

                In practice, I've found low level dark current not to be even a minor
                consideration and, if the cost in sensitivity is an ABG camera with a
                peak QE in the mid 60%s, I'm willing to live with that <g>.

                I'm glad you were given the opportunity to try out the camera and
                that you wrote your brief recap of your experience with it.

                Rick

                --- In ccd-newastro@yahoogroups.com, "Wodaski - Yahoo" <yahoo@w...>
                wrote:
                > I think you misunderstand. There would be no streaking from noisy
                pixels
                > that are below the visible threshold, just loss of clarity due to
                noise
                > (which, remember, is uncertainly in the brightness values of the
                signal). A
                > larger uncertainty in values is a hot pixel that you can see with
                the eye; a
                > smaller uncertainty in values simply robs the image of details by
                varying
                > the brightness values. If the eye spots hot pixels, then in my
                experience
                > the smaller noise is also present. But the smaller noise isn't
                necessarily
                > visible, even though it will have visible effects. It is much
                easier to
                > visualize the presence of something (a hot pixel) than an absence
                (details
                > that would have been there but for the noise). Thus a visual
                inspection by
                > its very nature is never rigorous enough to prove this point.
                >
                > All I'm asking is that you measure the noise instead of
                characterizing it by
                > eye - smaller noise levels are harder to judge, since the only
                evidence is
                > missing detail, which is hard to characterize. Measurements of
                standard
                > deviation are much more useful for making comparisons. I can't
                accept "no
                > noticeable" since the type of noise I'm talking about doesn't have
                > noticeable as a characteristic. <g> As with most noise, it is
                simply masking
                > signal, an effect that is impossible to measure directly. Std.
                Deviation is
                > a good correlation for most purposes, however, thus my request.
                >
                > What you would do is take equal exposure times winter and summer,
                and
                > measure the std. dev. of a background area with similar brightness
                levels.
                > This might require taking samples across a number of nights in the
                winter,
                > and a number of nights in the summer, so that you can find a
                reasonable
                > match. It would be interesting to do this again after a hot pixel
                removal;
                > that would go some way toward proving or disproving your hypothesis.
                >
                > Until then, motion denied. <g> Next case.
                >
                > Ron Wodaski
                > The New CCD Astronomy Book
                > web site: http://www.newastro.com
                >
                >
                > -----Original Message-----
                > From: Rick Krejci [mailto:randckrejci@y...]
                > Sent: Friday, January 02, 2004 1:50 PM
                > To: ccd-newastro@yahoogroups.com
                > Subject: [ccd-newastro] Re: Camera test report
                >
                > Streaking is a -very- common issue with beginners and is an
                > indication of improperly dark corrected image, whether it be from
                > using only a single dark with a series of lights or from using old
                > darks. It can certainly happen in all manufacturers cameras and is
                > certainly avoidable with good technique.
                >
                > And, in most cameras, you are correct that hot pixels are
                harbingers
                > of other noise. My very point was that this is not the case with
                the
                > SXV...the fact that there is no noticeable streaking pattern
                > discernable after removing the hot pixels indicates to me that any
                > remaining noise is well below the sky background, even for short Ha
                > exposures.
                >
                > Rick
                >
                >
                >
                > --- In ccd-newastro@yahoogroups.com, "Wodaski - Yahoo" <yahoo@w...>
                > wrote:
                > > What is the difference between summer and winter background
                standard
                > > deviation on equal exposure times? I can't reconcile "no need for
                > darks"
                > > with "more hot pixels." I'd like to get a handle on the actual
                > values, as I
                > > don't think Bob will let me keep the camera for 6 months. <g> To
                > me, hot
                > > pixels are just the obvious harbingers of less noticeable noise,
                > which a
                > > dark controls. Maybe one should be using darks in the summer, but
                > only a
                > > numerical analysis would demonstrate that, or not.
                > >
                > > If you are getting streaking from a full-frame chip, then it's
                more
                > likely
                > > an issue of technique. Properly done, there will be no streaking
                > (multiple
                > > darks, sufficient exposure times). The unvarnished truth would be
                > that you
                > > can get that result without darks using the SXV-H9, though of
                > course at a
                > > cost in sensitivity, so even though you don't need to take darks,
                > any time
                > > savings are reduced or eliminated. It becomes a matter of price,
                > software,
                > > support, documentation, and of course buyer preference as to
                which
                > type of
                > > camera to buy. The important things from the buyer's perspective
                is
                > that
                > > this camera is a useful tool. I used it with MaxIm DL, which I
                would
                > > strongly recommend.
                > >
                > > What is important to note is that the chip in this camera is an
                > advance over
                > > previous generations of the Sony chips, and the image quality is
                > improved. I
                > > wouldn't be surprised to see other vendors rallying around the
                > chip, though
                > > I know of no plans to do so. I certainly enjoyed using the chip,
                > but I'm
                > > going to go back to the ST-10XME as my regular camera. <g>
                > >
                > >
                > > Ron Wodaski
                > > The New CCD Astronomy Book
                > > web site: http://www.newastro.com
                > >
                > >
                > > -----Original Message-----
                > > From: Rick Krejci [mailto:randckrejci@y...]
                > > Sent: Friday, January 02, 2004 8:52 AM
                > > To: ccd-newastro@yahoogroups.com
                > > Subject: [ccd-newastro] Re: Camera test report
                > >
                > > Glad you liked it, Ron. You certainly got quite a bit of
                > production
                > > out of it!
                > >
                > > As far as higher temps, I use mine in about the hottest area
                you'll
                > > get, with summertime overnight temps staying in the 90's. I
                still
                > > had no need for darks, just relying on Maxim's hot pixel
                remover.
                > > There certainly was more hot pixels, but no more low-level noise
                > than
                > > when it's cold. And it's the lack of the low-level noise that
                > shows
                > > up in the dimmest backgrounds when stretched...I don't get that
                > > streaking effect when there is frame to frame drift.
                > >
                > > Rick
                > >
                > > --- In ccd-newastro@yahoogroups.com, "Wodaski - Yahoo"
                <yahoo@w...>
                > > wrote:
                > > > Bob Holzer sent me his SXV-H9 camera for some testing recently.
                > > I've been
                > > > imaging with it on the Tak Sky90 (with f/4.5 reducer). The
                small
                > > pixels of
                > > > this camera have been handy with such a short focal length
                > (400mm).
                > > Image
                > > > quality is very good, as you can see from the images I've been
                > > taking over
                > > > the last few days:
                > > >
                > > > http://www.blackbird-observatory.com/img/Sky90/SXV-H9/
                > > >
                > > > A few notes on some of the images:
                > > >
                > > > * The Horsehead image was taken with the camera newly inserted
                > into
                > > the
                > > > scope, and I think the camera was still warmer than the scope.
                > This
                > > led to
                > > > some elongation that looks like coma; it went away when the
                > > temperatures
                > > > equalized.
                > > >
                > > > * The color in one of the Sculptor Galaxy images is from an ST-
                > > 1001E image.
                > > >
                > > > * Most images were taken with 5-minute sub exposures. The
                > Sculptor
                > > images
                > > > were 10-minute sub exposures.
                > > >
                > > > * The Struve image was a test to see if a very dim nebula could
                > be
                > > detected
                > > > OK; it was - the nebula really is that dim. <g>
                > > >
                > > > The camera was easy to use, although it took a while to find
                and
                > > then figure
                > > > out how to install the software update (no readme). That's
                about
                > > the only
                > > > negative. No darks were used. Camera temperature was a chilly
                10-
                > 15
                > > degrees
                > > > for most of these images; I would be curious to see how it
                > performs
                > > > noise-wise in the summer time with higher ambient temperatures.
                > > >
                > > >
                > > > Ron Wodaski
                > > > The New CCD Astronomy Book
                > > > web site: http://www.newastro.com
                > >
                > >
                > >
                > >
                > > Yahoo! Groups Links
                > >
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                > >
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                > >
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                >
                >
                >
                >
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