Thanks Joe, The bubble object is the Crescent Nebula The faint reflection nebula in the top left is http://www.astrophotos.net/pages/Nebula/Vdb%20133.htm Cheers ;) On 8/15/2010 12:24 PM, Joe Bauman wrote:

Wonderful, David! Is that bubble nebula feature at the 7 o'clock position a known object? Best wishes, Joe

--- On Sun, 8/15/10, David Rankin<David@rankinstudio.com> wrote:

From: David Rankin<David@rankinstudio.com> Subject: [Utah-astronomy] 6 hours of Gamma Cygni To: "Utah Astronomy"<utah-astronomy@mailman.xmission.com> Date: Sunday, August 15, 2010, 12:58 PM

This image is 50 lights at 7 minutes each.

http://www.slas.us/gallery2/main.php?g2_itemId=3634&g2_imageViewsIndex=1

Enjoy!

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Really impressive, Don! Thanks, Joe --- On Mon, 8/16/10, Don J. Colton <djcolton@piol.com> wrote: From: Don J. Colton <djcolton@piol.com> Subject: Re: [Utah-astronomy] Imaging with the CGEM Mount To: "'Utah Astronomy'" <utah-astronomy@mailman.xmission.com> Date: Monday, August 16, 2010, 10:17 AM In my quest to find a portable mount for quick imaging the Celestron CGEM mount seems to be a good candidate.  I took the following images from my heavily light polluted backyard: http://www.slas.us/gallery2/main.php?g2_itemId=3637 and http://www.slas.us/gallery2/main.php?g2_itemId=3640 with the CGEM and a 250 mm Dall-Kirkham reflector with reducer giving an f ratio of 9.2 resulting in a focal length of 90.6 inches or 2300 mm.  I binned the images 2x2, but with 5.4 micron pixels on the camera this still gave an image scale of .96 arc seconds per 2x2 binned pixels. This is a fairly demanding image scale. I set up the mount by doing 2 alignment stars and three calibration stars. I then used the simple "All Star Polar Alignment" routine on Altair which took about five minutes. This routine gets you within about 5 arc minutes of perfect polar alignment if done properly - much better than the flimsy polar alignment scope that Celestron sells. Next I hooked up the autoguider to the camera guide port, slewed to the objects and used the freeware PhD guiding to begin guiding.  For M27 I took six, 4 minute luminances about half of which showed no guiding error and the others some slight guiding error. They were all combined in median combine using CCD Stack. For NGC 7331 I took four, 4 minute luminances and combined them using CCD Stack. When I slewed to M27 and NGC 7331 both were very close to the center of the field. I used the hand control unit to center M27 but didn't bother with NGC 7331. I have not yet trained the PEC or the DEC and RA backlash, which can be done with the software in the hand control unit, I just used the unit as it came out of the box except for updating the software via the web to the latest version.  When visually observing there was noticeable backlash in the hand control which can be improved with training.  PhD Guiding does compensate somewhat for backlash but I expect you could get better guiding if you train the backlash. In summary this is very good tracking for a $1400 mount considering I was carrying 35 lbs of equipment and utilizing a long focal length. _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com