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62161Stars focusing into lines

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  • Robert
    May 1, 2008
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      I need some help in figuring out a problem I am having getting a new
      camera setup in my scope. I am using an 8" reflector that is 1000mm
      with a DSI III pro.

      I have the DSI attached to a CFW8a filter wheel and use a MPCC coma
      corrector in the nosepiece.

      With this setup I get stars that look like little lines when it is
      just outside of focus. Images are producing stars that are very
      elongated.

      I can rule out guiding as a problem. I have used this my same scope
      setup and mount with a different camera and no guiding issues. The
      star problem shows up in images as fast as .2 seconds.

      I can also rule out colimation. The scope is well colimated and my
      DSLR in the same scope produces perfect stars.

      One thing I notice is when I check the focus on a bright star the
      diffraction spikes on one side dont converge. Normally when I get
      perfect focus all 4 spikes are perfect lines. With this camera setup
      I get 2 spikes as nice lines and 2 spikes split and blurred.

      Ok so now where do I look for the issue? My thought is this is some
      kind of tilt problem and I was wondering if the symptons match that
      assumption.

      My next step was to remove the CFW8 from the mix and try the camera
      straight through and if the problem lies with the camera itself.

      Any tips or tricks that might help me figure this one out?

      Thanks


      Robert
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