Gary, Nice work on the photos. Chuck's advice was excellent and I agree with everything he said. I thought I would mention another possible culprit for the jittery stars... shutter vibration! I have taken many images through my scopes with my digital SLR bodies, and I nearly always have problems with vibration unless I use a mirror lockup function. Many cameras have a way to flip up the mirror prior to taking the exposure. That procedure prevents the "snap" that can cause the whole assembly to shake. Take a look at the camera manual to see if your camera offers this function. Happy shooting! Tyler www.allred-astro.com _____________________________________________ -----Original Message----- From: utah-astronomy-bounces@mailman.xmission.com [mailto:utah-astronomy-bounces@mailman.xmission.com] On Behalf Of Gary Bulk Sent: Sunday, December 21, 2008 8:29 PM To: utah-astronomy@mailman.xmission.com Subject: [Utah-astronomy] Want feedback on my Orion Nebula picture flaws It's cloudy tonight, so I guess I'll send an email instead of looking at the stars. The Salt Lake southern skies cleared a little last night, so I took my friend's Celestron C8+ (8" CST with a motor drive - the one I'm dusting for him) and my Nikon D80 with a prime focus adapter out to my front porch and took some shots of the Orion Nebula. After about a 100 shots, I'm getting closer to a clear picture, but the problems are getting harder to figure out.. My Orion Nebula emphasizing the fuzzy stars: http://glogan.smugmug.com/gallery/6872266_UTskH/1/#440661533_PeEFc-A-LB The above link is a crop that shows fuzzy stars in the pictures. That was a 30sec. exposure at iso640. The stars definitely have movement, which I'm guessing is my poor polar alignment. My porch faces South and I can't see the North star from it, so I kept moving the tripod until the star trails got short (at the time I thought they went away). I am also wondering how long of an exposure I should expect to be able to get as far as accurate tracking using this Celestron C8+? But the stars should be smaller also, more pin-pointish. I can't seem to be certain of my focus through my camera viewfinder, as the stars are too dim. Are there techniques or equipment that others use to help focus when mounting a camera? Also, (whine) the Celestron seems to have a pretty coarse focus knob, even with the regular eyepieces. My best Orion: http://glogan.smugmug.com/gallery/6872266_UTskH/1/#440655195_68tXH-A-LB Regards Gary Logan _____ _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://gallery.utahastronomy.com Visit the Wiki: http://www.utahastronomy.com