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Re: NGC 2392 9"f/18 !!!

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  • Tube Tim
    ... We don t need no stickin colour. Very well done. This is the best Eskimo I have seen so I would say your 2x barlow and test CCD are working. How were you
    Message 1 of 5 , Jan 9, 2008
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      >--- In tmboptical@yahoogroups.com, "dietmar hager"
      > <dietmar.hager@...> wrote:
      >
      > hey - what is that? luminance only...? no color...?
      >

      We don't need no stickin' colour.

      Very well done. This is the best Eskimo I have seen so I would say
      your 2x barlow and test CCD are working.

      How were you able to guide this?


      > frankly, it is embarrassing enough when I admit this luminance image
      > you see in the full size is already a 50% crop, as my f/9 system
      > illuminantes the chip nicely, but fails to cast nice round stars
      > onto the chip all over the area. what waste of pixels...!
      >

      It's the physics, nothing to be embarassed about. :-)


      Tim
    • dietmar hager
      ...thanks Neil and Tim. Tim, I guided with my 5 f/9 on prime focus without any problem. Neil, it is not a matter of different sizes,...it is a matter of
      Message 2 of 5 , Jan 9, 2008
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        ...thanks Neil and Tim.

        Tim, I guided with my 5"f/9 on prime focus without any problem.

        Neil, it is not a matter of different sizes,...it is a matter of
        completely different field curvature.
        the very central parts (let'S say20% of the chip or less) would
        fit,...the rest is a disaster...

        Dietmar


        --- In tmboptical@yahoogroups.com, "Tube Tim" <potentate@...> wrote:
        >
        > >--- In tmboptical@yahoogroups.com, "dietmar hager"
        > > <dietmar.hager@> wrote:
        > >
        > > hey - what is that? luminance only...? no color...?
        > >
        >
        > We don't need no stickin' colour.
        >
        > Very well done. This is the best Eskimo I have seen so I would say
        > your 2x barlow and test CCD are working.
        >
        > How were you able to guide this?
        >
        >
        > > frankly, it is embarrassing enough when I admit this luminance
        image
        > > you see in the full size is already a 50% crop, as my f/9 system
        > > illuminantes the chip nicely, but fails to cast nice round stars
        > > onto the chip all over the area. what waste of pixels...!
        > >
        >
        > It's the physics, nothing to be embarassed about. :-)
        >
        >
        > Tim
        >
      • Michael Sherick
        Interesting image and facinating detail. Mike ... dietmar hager wrote: hey - what is that? luminance only...? no color...? well, this is
        Message 3 of 5 , Jan 10, 2008
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          Interesting image and facinating detail.

          Mike

          ---------------------------------------------------------------------

          dietmar hager <dietmar.hager@...> wrote:
          hey - what is that? luminance only...? no color...?

          well,
          this is a result of an experiment I conducted last night when seeing
          was really very good for a short periode.
          I used a monochromatic demo-CCD SXVF H36, my 9" TMB apo but this time
          @ f/18 !
          I slammed in the 2" 2* big barlow cos I wanted to see, if the system
          is powerful enough to allow imaging bright small planetary nebulas -
          which shall become one of my future tasks,...I hope.

          singel frames were only 4 minutes 'short' and it worked nicely!
          the backgroundsingal shows a very comfortable low noise at 0┬░celsius
          ambient. even though the chip is a engen.grade type artefacts are
          negligable and are easy to handle.
          I also took rgb files, but in primary focus at f/9.
          today when preprocessing the data the bad news came along:

          after completing luminance and r,g,b seperatly I wanted to registar
          and align these 2 master-frames.
          but - no chance to do so! no software I used was able to stack these
          two successfully!

          I really did not expect this in the fist place.

          I often use f/9 data and combine it with f/7 data, when I use my
          reducer/flattener.

          but obviously there is a big difference in what happens to the field
          when trying to combine f/9 and f/18...
          I would have had to crop the image so dramatically that I refused to
          do so,...cos it would have been to embarrassing...

          frankly, it is embarrassing enough when I admit this luminance image
          you see in the full size is already a 50% crop, as my f/9 system
          illuminantes the chip nicely, but fails to cast nice round stars onto
          the chip all over the area.
          what waste of pixels...!

          so - I N E E D a decent flattener for my 9" TMB Apo f/9.
          (and one is already on its way...)

          in future when imaging with the barlow, which I will continue, I'll
          have to do my r,g,b files also with the barlow lenses...will be
          intersting to see if this works at a reasonalbe amount of exposure
          time...?

          data:
          8.1.08:
          9" f/18 (TV 2" 2* big barlow)
          SXVF H36 (50% crop)
          18x4 minutes single frams
          7 darkframes

          image acquisition: AA4
          preprocessing (dark-calibration, kernel filtering, alignment,
          stacking and Deconv. in maxim dl)
          pre-sharpening in CCD sharp. DDP in Maxim DL.
          postprocessing in PS CS2.

          full size (crop) can be found here:
          http://www.stargazer-observatory.com/2392-full-L.html

          an enlarged crop is here:
          http://www.stargazer-observatory.com/2392-enl-crop-L.html

          thanks for looking,

          Dietmar






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