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Re: Color balance confusion

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  • richardl@well.com
    There s no rush. I ll be out of town, and I won t be able to look at this for about 10 days. In the mean time I m finding loads of interesting reading about
    Message 1 of 6 , Apr 3, 2001
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      There's no rush. I'll be out of town, and I won't be able to look at
      this for about 10 days.

      In the mean time I'm finding loads of interesting reading about CCD
      imaging in Richard Berry's Handbook of Astronomical Image Processing.

      Thanks again.

      - Richard Lawler

      --- In ccd-newastro@y..., "Ron Wodaski" <ronw@n...> wrote:
      > Got the ZIP downloaded, will look at it first chance I get.
      >
      > Ron Wodaski
      > The New CCD Astronomy
      > http://www.newastro.com
      >
      > -----Original Message-----
      > From: richardl@w... [mailto:richardl@w...]
      > Sent: Monday, April 02, 2001 9:35 PM
      > To: ccd-newastro@y...
      > Subject: [ccd-newastro] Re: Color balance confusion
      >
      >
      > Thanks Ron,
      >
      > I've uploaded a Zip file with one set (from a sequence of ten sets)
      > of unprocessed R, G, and B fits files. These were 60 seconds each.
      ST-
      > 237 w/ internal color wheel, C8 at F/3. Images captured in
      > MaximDL/CCD.
      >
      > The Zip file is
      > http://groups.yahoo.com/group/ccd-newastro/files/Feedback/RJL-ST237-
      > M51-RGB.zip
      >
      >
      > - Richard Lawler
      > (richardl@w...)
      > http://www.well.com/user/richardl/astro
      > N8, T-SG4 & G8/GP-DX/SS2K
      > 122:27:48W
      > 37:44:13N
      >
      > --- In ccd-newastro@y..., "Ron Wodaski" <ronw@n...> wrote:
      > > It's hard to say without looking at the raw files. If you want to
      > make a ZIP
      > > file of one R, one G, one G, and send them to me, I will take a
      > look. This
      > > should be _before_ you do any flat fields or dark subtraction (aka
      > > Calibration in Maxim DL). Send them to my personal email address,
      > or upload
      > > the ZIP file to the Feedback section of the Files area at:
      > >
      > > http://groups.yahoo.com/group/ccd-newastro/files/Feedback/
      > >
      > > Ron Wodaski
      > > The New CCD Astronomy
      > > http://www.newastro.com
      > >
      > > -----Original Message-----
      > > From: richardl@w... [mailto:richardl@w...]
      > > Sent: Monday, April 02, 2001 4:17 PM
      > > To: ccd-newastro@y...
      > > Subject: [ccd-newastro] Color balance confusion
      > >
      > >
      > > Newbie alert!
      > >
      > > I've got my new ST-237 with optional color wheel trying to do some
      > > RGB imaging. My first night out with the new camera and I
      learning
      > to
      > > use this thing. Got focus working, got aiming working, Wow! there
      > are
      > > the galaxies. Cool. So I did some integrations of M81 and M51.
      > > (Through a C8 with an f/3.3 Meade reducer corrector. Actually it's
      > > supposed to be closer to f/3 in the configuration I'm using --
      > > screwed into the visual back with the camera mounted in the
      eyepiece
      > > adapter.)
      > >
      > > I did my integrations with MaximDL using equal exposures for RGB.
      My
      > > problem (or maybe just my lack of understanding) is that when I
      > > combine these images to get color I get a very red result if I use
      > > equal weighting for R-G-B. Things look reasonable when I set the
      > > color balance to approx R = 0.3, G = 1.0, B = 1.0.
      > >
      > > What's going on here? According to SBIG this color wheel is
      supposed
      > > to be about equally balanced:
      > > http://www.sbig.com/sbwhtmls/filterchart.htm
      > >
      > > Am I doing something wrong? Any idea why I'm so far off?
      >
      >
      >
      >
      > To unsubscribe from this group, send an email to:
      > ccd-newastro-unsubscribe@egroups.com
      >
      >
      >
      > Your use of Yahoo! Groups is subject to
      http://docs.yahoo.com/info/terms/
    • richardl@well.com
      I finally solved this problem after much head scratching and running a white-balance tests with a Sun-like reference star. It turns out I had MaximDL/CCD
      Message 2 of 6 , Apr 18, 2001
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        I finally solved this problem after much head scratching and running
        a white-balance tests with a Sun-like reference star. It turns out I
        had MaximDL/CCD incorrectly configured for tricolor imaging and was
        using the wrong filters: L-R-G rather than R-G-B. So that's why
        everything was looking so red.

        I now seem to have things working well. Now I just need the fog to
        clear.

        Thanks.

        - Richard Lawler

        --- In ccd-newastro@y..., richardl@w... wrote:
        > Thanks Ron,
        >
        > I've uploaded a Zip file with one set (from a sequence of ten sets)
        > of unprocessed R, G, and B fits files. These were 60 seconds each.
        ST-
        > 237 w/ internal color wheel, C8 at F/3. Images captured in
        > MaximDL/CCD.
        >
        > The Zip file is
        > http://groups.yahoo.com/group/ccd-newastro/files/Feedback/RJL-ST237-
        > M51-RGB.zip
        >
        >
        > - Richard Lawler
        > (richardl@w...)
        > http://www.well.com/user/richardl/astro
        > N8, T-SG4 & G8/GP-DX/SS2K
        > 122:27:48W
        > 37:44:13N
        >
        > --- In ccd-newastro@y..., "Ron Wodaski" <ronw@n...> wrote:
        > > It's hard to say without looking at the raw files. If you want to
        > make a ZIP
        > > file of one R, one G, one G, and send them to me, I will take a
        > look. This
        > > should be _before_ you do any flat fields or dark subtraction (aka
        > > Calibration in Maxim DL). Send them to my personal email address,
        > or upload
        > > the ZIP file to the Feedback section of the Files area at:
        > >
        > > http://groups.yahoo.com/group/ccd-newastro/files/Feedback/
        > >
        > > Ron Wodaski
        > > The New CCD Astronomy
        > > http://www.newastro.com
        > >
        > > -----Original Message-----
        > > From: richardl@w... [mailto:richardl@w...]
        > > Sent: Monday, April 02, 2001 4:17 PM
        > > To: ccd-newastro@y...
        > > Subject: [ccd-newastro] Color balance confusion
        > >
        > >
        > > Newbie alert!
        > >
        > > I've got my new ST-237 with optional color wheel trying to do some
        > > RGB imaging. My first night out with the new camera and I
        learning
        > to
        > > use this thing. Got focus working, got aiming working, Wow! there
        > are
        > > the galaxies. Cool. So I did some integrations of M81 and M51.
        > > (Through a C8 with an f/3.3 Meade reducer corrector. Actually it's
        > > supposed to be closer to f/3 in the configuration I'm using --
        > > screwed into the visual back with the camera mounted in the
        eyepiece
        > > adapter.)
        > >
        > > I did my integrations with MaximDL using equal exposures for RGB.
        My
        > > problem (or maybe just my lack of understanding) is that when I
        > > combine these images to get color I get a very red result if I use
        > > equal weighting for R-G-B. Things look reasonable when I set the
        > > color balance to approx R = 0.3, G = 1.0, B = 1.0.
        > >
        > > What's going on here? According to SBIG this color wheel is
        supposed
        > > to be about equally balanced:
        > > http://www.sbig.com/sbwhtmls/filterchart.htm
        > >
        > > Am I doing something wrong? Any idea why I'm so far off?
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