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Bubble in Ha from 18 cass (flat fielded)

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  • rdcrisp
    here is the first image from the 18Cass taken with a flat field. the seeing was lousy tonight unfortunately. The guidestar was dancing all around the ao7
    Message 1 of 6 , Oct 31, 2004
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      here is the first image from the 18Cass taken with a flat field.

      the seeing was lousy tonight unfortunately. The guidestar was dancing
      all around the ao7 control window

      stil this was shot at F=5760mm (f/12.6) with an IMG6303 binned 2x2.
      It is 5 shots of 20 minutes through a schuler Ha filter. I was
      measuring FWHM of the smaller stars in the subframes at 3.4 to 3.9
      arc-seconds.

      the image scale is 0.64 arc-sec/pixel in the full resolution image

      http://www.narrowbandimaging.com/ngc7635_18cass_page.htm

      it figures that when I am really ready to shoot images the first
      clear night has to be bad seeing.

      The new cass will have to wait a little longer to strut its stuff

      rdc
    • aajohnah
      Looking real good You are going to have a real winner there Was curious if the right side of the image shows elongated stars where the left side does not? Is
      Message 2 of 6 , Nov 1, 2004
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        Looking real good
        You are going to have a real winner there
        Was curious if the right side of the image shows elongated stars where the
        left side does not? Is it my monitor, or maybe something not squared?

        Mark
        www.aajonahfish.com/astronomyhaven.htm

        ----- Original Message -----
        From: "rdcrisp" <rdcrisp@...>
        To: <ccd-newastro@yahoogroups.com>
        Sent: Monday, November 01, 2004 2:46 AM
        Subject: [ccd-newastro] Bubble in Ha from 18 cass (flat fielded)


        >
        >
        > here is the first image from the 18Cass taken with a flat field.
        >
        > the seeing was lousy tonight unfortunately. The guidestar was dancing
        > all around the ao7 control window
        >
        > stil this was shot at F=5760mm (f/12.6) with an IMG6303 binned 2x2.
        > It is 5 shots of 20 minutes through a schuler Ha filter. I was
        > measuring FWHM of the smaller stars in the subframes at 3.4 to 3.9
        > arc-seconds.
        >
        > the image scale is 0.64 arc-sec/pixel in the full resolution image
        >
        > http://www.narrowbandimaging.com/ngc7635_18cass_page.htm
        >
        > it figures that when I am really ready to shoot images the first
        > clear night has to be bad seeing.
        >
        > The new cass will have to wait a little longer to strut its stuff
        >
        > rdc
        >
        >
        >
        >
        >
        >
        >
        >
        >
        >
        > Yahoo! Groups Links
        >
        >
        >
        >
        >
        >
        >
        >
      • rdcrisp
        ... where the ... squared? Probably the latter. there are lots of knobs to adjust, I probably missed some. rdc
        Message 3 of 6 , Nov 1, 2004
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          --- In ccd-newastro@yahoogroups.com, "aajohnah" <aajohnah@t...> wrote:
          > Looking real good
          > You are going to have a real winner there
          > Was curious if the right side of the image shows elongated stars
          where the
          > left side does not? Is it my monitor, or maybe something not
          squared?


          Probably the latter. there are lots of knobs to adjust, I probably
          missed some.
          rdc
        • Michael Downing
          Looks Like you are on the Richard Seems to be some noise in there, I would guess @f12.5 your going to need to bake that chip data :-) Michael Downing
          Message 4 of 6 , Nov 1, 2004
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            Looks Like you are on the Richard

            Seems to be some noise in there, I would guess @f12.5 your going to need to
            bake that chip data :-)



            Michael Downing

            www.astroden.com <http://www.astroden.com/>







            _____

            From: rdcrisp [mailto:rdcrisp@...]
            Sent: Monday, November 01, 2004 2:47 AM
            To: ccd-newastro@yahoogroups.com
            Subject: [ccd-newastro] Bubble in Ha from 18 cass (flat fielded)




            here is the first image from the 18Cass taken with a flat field.

            the seeing was lousy tonight unfortunately. The guidestar was dancing
            all around the ao7 control window

            stil this was shot at F=5760mm (f/12.6) with an IMG6303 binned 2x2.
            It is 5 shots of 20 minutes through a schuler Ha filter. I was
            measuring FWHM of the smaller stars in the subframes at 3.4 to 3.9
            arc-seconds.

            the image scale is 0.64 arc-sec/pixel in the full resolution image

            http://www.narrowbandimaging.com/ngc7635_18cass_page.htm

            it figures that when I am really ready to shoot images the first
            clear night has to be bad seeing.

            The new cass will have to wait a little longer to strut its stuff

            rdc















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          • rhoowl@yahoo.com
            HI richard i was looking at the frame of your telescope...seems to deflections would be a problem for the frame...i ran a finite element analysis of a hooped
            Message 5 of 6 , Nov 1, 2004
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              HI richard

              i was looking at the frame of your telescope...seems to deflections
              would be a problem for the frame...i ran a finite element analysis of
              a hooped telescope like your and found that deflections were
              unacceptable...but when you add diagonal braces to the scope the
              deflections came to acceptable limits...we can only visually detect
              deflections less than about 1 in 30...probably to hold the deflection
              to a acceptable limit it would have to be on order of 1 in a 500..the
              telescope i analyzed has deflection of about 1 in 50...

              jamie


              --- In ccd-newastro@yahoogroups.com, "rdcrisp" <rdcrisp@e...> wrote:
              >
              > here is the first image from the 18Cass taken with a flat field.
              >
              > the seeing was lousy tonight unfortunately. The guidestar was
              dancing
              > all around the ao7 control window
              >
              > stil this was shot at F=5760mm (f/12.6) with an IMG6303 binned 2x2.
              > It is 5 shots of 20 minutes through a schuler Ha filter. I was
              > measuring FWHM of the smaller stars in the subframes at 3.4 to 3.9
              > arc-seconds.
              >
              > the image scale is 0.64 arc-sec/pixel in the full resolution image
              >
              > http://www.narrowbandimaging.com/ngc7635_18cass_page.htm
              >
              > it figures that when I am really ready to shoot images the first
              > clear night has to be bad seeing.
              >
              > The new cass will have to wait a little longer to strut its stuff
              >
              > rdc
            • rdcrisp
              ... of ... thanks for taking the time to analyze it Jamie. unfortunately the photos don t totally reveal all the details of the construction including the
              Message 6 of 6 , Nov 1, 2004
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                --- In ccd-newastro@yahoogroups.com, rhoowl@y... wrote:
                >
                > HI richard
                >
                > i was looking at the frame of your telescope...seems to deflections
                > would be a problem for the frame...i ran a finite element analysis
                of
                > a hooped telescope like your and found that deflections were
                > unacceptable...but when you add diagonal braces to the scope the

                thanks for taking the time to analyze it Jamie. unfortunately the
                photos don't totally reveal all the details of the construction
                including the thicknesses and shapes of the various structural
                members. As you likely know the analysis is only as good as the model
                and without working from an accurate mechanical representation (ie
                autocad files) the model will be wrong.

                I've done lots of simulations in my life and I know that if the model
                isn't right neither are the simulation results.

                But irrespective of the results of your analysis, I am finding the
                scope holds collimation well when tested in the horizontal facing
                east versus horizontal facing west versus horizontal facing north
                versus horizontal facing south positions. Those extremes are the
                worst case in terms of lateral deflections of the structural members
                and it looks like I got lucky and thing are holding together well.

                initially i saw some collimation shifts but I discovered my primary
                mirror wasn't properly adjusted. Once I did that it is holding rock
                solid.

                If you want to explore the details, I suggest you contact Mark
                Wagner, the designer and seller of the frame. He has the Autocad
                files. There's a link to Resource International on my webpage. That's
                Mark's company.

                At the moment my biggest mechanical concern is shielding it from wind
                if it picks up like when I am on Fremont Peak. It has a very long
                moment arm on the dec axis.

                best regards
                Richard
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