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Comet C/2007 N3 Lulin Still a good Target

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  • Dennis Persyk
    Comet C/2007 N3 Lulin is fading rapidly into the western sky. But it is still a good target, with a 20 arc minute long tail, magnitude about 9.5, and fairly
    Message 1 of 1 , Apr 23, 2009
      Comet C/2007 N3 Lulin is fading rapidly into the western sky. But it is still a good target, with a 20 arc minute long tail, magnitude about 9.5, and fairly high in Gemini. It also has an incredibly slow relative motion of only 0.01 arc seconds/minute, so you can take long exposures without blurring the comet.

      Last night I imaged it under terrible seeing, but fortunately one doesn't need good seeing to image a comet. When I focus using AstroArt 3.0, a medium bright (mag 8 star) lights up just one pixel in focus mode. Last night the focus image was bouncing back and forth between 4 and 7 pixels! Probably 6 or 7 arc second RMS seeing. But I got a reasonable image at 5.0 arc seconds per pixel (binned 2x2).

      My sky brightness was 19.0 magnitudes/ square arc second (measured with a Sky Quality Meter, as my 68 year old eyes aren't very sensitive any more). That translates into an NELM (naked-eye limiting magnitude) of about 4.7. I live 40 miles west of Chicago.

      Images, associated data, and imaging notes at
      http://home.att.net/~dpersyk/new.htm

      Thank you for visiting my site.

      Clear skies,

      Dennis Persyk
      Igloo Observatory Home Page http://dpersyk.home.att.net
      Hampshire, IL

      Pier Design Paper: http://home.att.net/~dpersyk/Pier_Design.htm
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