Hercules Cluster or Abel 2151
Telescope: 16″ f3.75 Dream Scope
Camera: FLI ML16803
Mount: ASA DDM85
Exposure: 75x5min L + 35x5min each for RGB
Date: March – April 2017
Location: Southern Alps, France
Data acquisition: Karel Teuwen and Bart Delsaert
Processing: Bart Delsaert
Spring is typically the time of year for galaxy hunting. So why not try to capture as many galaxies as possible in one single frame? When you point your telescope in between the constellations of Hercules and Serpens you might come pretty close to the expectations.
The Hercules Cluster of Galaxies contains about 200 member galaxies, some 500 million light-years distant, with a wide range of mostly spiral galaxies, a smaller number of elliptical galaxies, and a healthy collection of colliding galaxies. This image clearly shows the contrasting colors of younger star forming galaxies which are primarily blue, while older galaxies are mostly yellow.
Update May 2nd, 2017: I’ve created an inverted, annotated image of the area. The annotations are coming from the NGC, IC and PGC catalogues. The PGC catalogue goes up to magnitude 18, but you can clearly see a lot of much fainter galaxies without catalogue number.