Galaxy Cluster in Hercules
(Roll over image for object labels)
The Hercules Galaxy Cluster includes about 300 galaxies and is located about 500 million light years away. This image shows the central region, but the cluster extends beyond the field of view seen here. The galaxies have a wide variety of shapes, and there are quite a few groups of two or more interacting galaxies.
In a region crowded with galaxies like this, early astronomers had some difficulty recording the precise locations of all these dim objects, which led to some duplication of numbering in the New General Catalog, first published by J. L. E. Dreyer in 1888. For example, as can be seen by rolling over the image, NGC 6039 and 6042 refer to the same galaxy.
A particularly interesting member of this group is IC 1182, which seems to have two jets streaming to its left, one of them quite some distance away. According to one current theory, these are "tidal tails" that are the result of two merging galaxies. These jets can be seen more clearly in this larger image.
Several of the brightest galaxies are well within the range of telescopes with medium to large apertures, making this one of the most distant galaxy groups that can be seen by amateur astronomers.
Image details: Exposure times of 225 minutes luminance, and 30 minutes each of red, green, and blue, taken with an SBIG ST-8300M imager and a 14" Meade LX850 telescope at f/6.