Lorenzo Comolli's Astronomy HomePage

Click on the image for the high res version (100% res and full field) - mouse over for galaxy labels

The most celebrated galaxy cluster of Coma Berenices (and of the whole sky) is without doubt the Virgo-Coma galaxy cluster. But nearby (in the sky, 16°) and much further (in the space, 330 Mly vs. 54 Mly) lies Abell 1656. This cluster is composed of over 1000 galaxies, most of them are packed in the central part (seen above). For a better view take a look at the full field and full resolution by clicking on the image.

Technical Data
Optics	TEC 140
Focal Length	1011 mm
Focal Ratio	f/7.2
Exposure Time	8 h 20 min (single exp of 10 min), LRGB 240:80:70:110 min
CCD	SBIG STL-11000M @-40°C
Location	Pian dell'Armà (PV, Italian Apennines) at 1350 m height
Date	8-9 February 2013 (two nights)
Mount	Gemini G-41
Tracking	Lodestar on an 80mm f/5 refractor
Temperature and humidity	T= -13 °C, RH=50%
Sky brightness at zenith (with SQM-L)	21.3-21.4 mag/arcsec^2
Notes	North at top. Labels from Perseus software.