From locations with dark skies, some members of the Pegasus I Galaxy Cluster can be seen with moderately sized amateur telescopes, to the east of the summer Milky Way in the constellation Pegasus. From my suburban location it is no longer possible to see these galaxies with my 8-inch reflector telescope due to steadily increasing light pollution, but my camera can still capture them with long exposures.

The Pegasus group lies approximately 200 million light years distant from Earth. This photo shows 17 of the brightest member galaxies. The two brightest members, NGC-7619 and NGC-7626, are approximately magnitude 12, making them challenging but still possible to glimpse with an 8-inch reflector under sufficiently dark skies.

In this image the 17 brightest galaxies are labelled with their catalog numbers. Most of them are recorded in the NGC (New General Catalog), which was compiled in the 1880's and contains 7,840 deep space objects. Those member galaxies not found in the NGC are cataloged in the Catalog of Principal Galaxies (PGC, compiled in 1989), the Uppsala Galaxy Catalog (UGC, compiled in 1973) or the Index Catalog (IC, compiled in the 1880's as an appendix to the NGC).

If you view this image at its original size, you may see more galaxies that I have not labelled - there are perhaps 15 or 20 fainter galaxies visible here.

The brightest star in this image is designated HD-219949 (from the Henry Draper catalog of 359,000 stars). It's visual magnitude is approximately 7, making it invisible to the naked eye under even the darkest skies. Like all of the stars visible in this image, HD-219949 is much closer to Earth than the Pegasus I Galaxy Cluster, being in our own Milky Way galaxy. The spikes visible on the image of HD-219949 and other bright stars are called diffraction spikes, and they are characteristic of star images acquired with Newtonian reflectors. They result from diffraction patterns caused by the secondary mirror support vanes in telescopes that have those support vanes, including the famous Hubble Space Telescope.

This image is a composite of 25 three minute exposures at ISO 800, captured with my Canon Digital Rebel XT (350D) at the prime focus on my 8 inch reflector. The new moon had set two to three hours before these images were captured. The raw images were processed along with 50 bias frames, 16 dark frames, 16 flat frames and 16 dark-flat frames, using Iris software, and the result was touched up in Adobe Photoshop CS5. A significant amount of noise remains in the final result, due to the severe sky glow caused by light pollution that I had to overcome.

The telescope was mounted on an Orion Atlas EQ-G, controlled using the amazing open source EQMOD driver with Cartes du Ciel planetarium software. Autoguiding was accomplished with PHD Guiding software from Stark Labs, utilizing a Meade DSI-C CCD camera attached to an Orion 80mm f/11 achromatic refractor telescope. Long exposure image acquisition using the Canon Digital Rebel XT was accomplished with DSLR Focus software.