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RE: [ccd-newastro] First calibrated image

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  • Wodaski Yahoo account
    First, that s a really nice M101. Details are sharp, stars are really round - a neat effort. The flat fielding must be good, too, because I see no evidence of
    Message 1 of 6 , May 1, 2003
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      First, that's a really nice M101. Details are sharp, stars are really
      round - a neat effort. The flat fielding must be good, too, because I see no
      evidence of any flaws.

      Ron Wodaski
      author of The New CCD Astronomy
      http://www.newastro.com


      -----Original Message-----
      From: Frank Barrett [mailto:frankb02@...]
      Sent: Wednesday, April 30, 2003 4:08 PM
      To: ccd-newastro@yahoogroups.com
      Subject: [ccd-newastro] First calibrated image


      Here's my first attempt at a fully calibrated image with my new
      light box. In keeping with the recent theme it is, of course, of
      M101 ;)
      I'm just a bit concerned over the noise in this image. I would have
      thought that an hour long exposure would not have resulted in so
      much noise in the faint arms. Am I overstretching this with curves?

      http://celestialwonders.com/m101b-st7.html

      Thanks, Frank
      http://celestialwonders.com



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    • Frank Barrett
      Randy, Paul, Don, and Ron, Thanks, I feel very encouraged by your warm responses. The lightbox seems to be working out quite well. When I first got the white
      Message 2 of 6 , May 1, 2003
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        Randy, Paul, Don, and Ron,

        Thanks, I feel very encouraged by your warm responses.
        The lightbox seems to be working out quite well. When I first got
        the white acrylic sheets I thought there was no way those 4 little
        LEDs could shed enough light, but it really works. Thanks again to
        Don for sharing his plans.
        Polar alignment indeed was very good this night, but I have to give
        some credit to the new worm of the G11 as well. I haven't done the
        math on this setup but I think it's in the neighborhood of 3-4
        arcsecs per pixel. I haven't measured PE on this mount but I'm
        guessing it must be in that neighborhood, no?
        Indeed the flats look good. With the f/3.3 FR on the C8 I get a very
        noticeable hot spot, which up till now I've been trying to remove
        (unsuccessfully) in Photoshop. With the flats it's completely
        removed. I love it!
        Let me end with one question. Since this is a brand new camera I
        haven't had the opportunity to get it dirty <g> and I see no dust
        motes or donuts on the flats. I have some images from a couple weeks
        ago taken with the exact same setup which have not been flat
        fielded. Any harm in applying these flats to those images?

        Frank
        http://celestialwonders.com

        --- In ccd-newastro@yahoogroups.com, "Wodaski Yahoo account"
        <yahoo@w...> wrote:
        > First, that's a really nice M101. Details are sharp, stars are
        really
        > round - a neat effort. The flat fielding must be good, too, because
        I see no
        > evidence of any flaws.
        >
        > Ron Wodaski
        > author of The New CCD Astronomy
        > http://www.newastro.com
        >
        >
        > -----Original Message-----
        > From: Frank Barrett [mailto:frankb02@b...]
        > Sent: Wednesday, April 30, 2003 4:08 PM
        > To: ccd-newastro@yahoogroups.com
        > Subject: [ccd-newastro] First calibrated image
        >
        >
        > Here's my first attempt at a fully calibrated image with my new
        > light box. In keeping with the recent theme it is, of course, of
        > M101 ;)
        > I'm just a bit concerned over the noise in this image. I would have
        > thought that an hour long exposure would not have resulted in so
        > much noise in the faint arms. Am I overstretching this with curves?
        >
        > http://celestialwonders.com/m101b-st7.html
        >
        > Thanks, Frank
        > http://celestialwonders.com
        >
        >
        >
        > 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/
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