This immense galaxy cluster in Coma Berenices contains thousands of galaxies. The largest two, NGC 4874 and 4889, are bright enough to be seen in even a small telescope. Others are so dim that they probably have never been observed visually, but they can be captured with long-duration photographs.

This image is based on a total exposure time of about 130 minutes. The yellow marks in the roll-over image identify about 175 galaxies from the Principal Galaxy Catalog, which list galaxies to about magnitude 19.9. I also used Google Sky to identify about 145 other galaxies, shown by the red marks. Some of the other dim points in this image are also galaxies, but they were so small in the Google Sky image that it was difficult to tell which were distant galaxies and which were stars.

Image details:  53 images, each 150 seconds at ISO 1600, taken with a Canon 400D camera through a Meade 12” telescope at f/6.7.  Image processing with ImagesPlus and Photoshop.

May 2010