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60810Re: [ccd-newastro] focusing dslr

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  • tim hart
    Jan 5, 2008
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      Thanks for the great information Ron, Murry and Bill.
      ----- Original Message -----
      From: Yahoo - Wodaski
      To: ccd-newastro@yahoogroups.com
      Sent: Tuesday, January 01, 2008 1:33 PM
      Subject: Re: [ccd-newastro] focusing dslr


      I tried one of these a few years ago, and I wasn't very happy with it
      for digital photography. Given that the cost of software is roughly
      similar, and that software gives you tons of other options and features
      as well, I would recommend going the software route. I've used MaxIm DL
      for my DSLR work, and while it's considerably more than $250, it does
      work extremely well. <G>

      I know a number of DSLR images who use Images Plus and are very happy
      with that, so that's another option.

      The Stilleto got its start in film, where digital acquisition is not
      available, and I think it's primary value remains in that area. Even
      there, it requires extremely careful physical manipulation to work well.
      Film has a larger effective "pixel size" than CCD; the small pixels in
      DSLRs makes this even more critically important. I found it virtually
      impossible to maintain consistency that was adequate to the requirements
      of CCD sensors in astro cameras (figure 7-9 micron pixels); DSLRs often
      have even smaller pixels, making focus that much more critical. IMO,
      software image acquisition is the way to go.

      Ron Wodaski

      Murray Hammick wrote:
      > You can also use a separate focusing aid such as the Stilleto Mk IV which can sometimes be found second-hand on Astromart or similar sites for reasonable prices. A new one is in the order of about $250 (I think).
      >
      > Murray
      >
      >
      >
      >
      > Bill Logan <wb9sat@...> wrote: Digital cameras, unlike film cameras must be fine focused on the pixel
      > level. You can get a rough focus through the viewfinder, but final focusing
      > must be done by looking at FWHM (Full-Width, Half Maximum) numbers. You can
      > use an inexpensive digital capture and processing program such as Stark-Labs
      > Nebulosity. Nebulosity has a fine focus routine that allows you to fine
      > focus using FWHM.
      >
      > Clear skies,
      >
      > Bill Logan
      > Robert Burnham Jr. Memorial Observatory
      >
      > http://tech.groups.yahoo.com/group/Exoplanet_Astronomers/
      >
      > ----- Original Message -----
      > From: "firebirdthart" <thart40@...>
      > To: <ccd-newastro@yahoogroups.com>
      > Sent: Monday, December 31, 2007 5:36 PM
      > Subject: [ccd-newastro] focusing dslr
      >
      > > Is there a better way to focus the canon xti than through the view
      > > finder, any way to send image to computer possibly?
      > >
      > >
      > >
      > > Yahoo! Groups Links
      > >
      > >
      > >
      > >
      > >
      > >
      > > --
      > > No virus found in this incoming message.
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      > > 12/31/2007 12:20 PM
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      > [Non-text portions of this message have been removed]
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      >
      > Yahoo! Groups Links
      >
      >
      >




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