UGC 4991 - Galaxy Group
UGC 4991 is an elliptical galaxy in a group of the same name, which is located in the constellation Coma Berenices and can be best observed in spring.
The galaxy has a redshift of z=0.034 and is moving away from us at a speed of 10,000 km/s. Its diameter is around 115,000 light-years and from the
apparent brightness of 15.2mag, the absolute magnitude can be determined as M= -20.6mag, which corresponds to a luminosity of 15 billion suns. In
the sky it appears as large as the planet Jupiter.
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This group of galaxies is a small challenge even in a 20" telescope and therefor requires a dark sky, because the small galaxies are only 15...16mag bright.
At a magnification of 380x I could see 9 galaxies, 5 of them in the inner part of the group. They were actually quite easy to see with averted vision,
but showed no specific structures. Nevertheless, it was quite nice to look at this probably unobserved group.
A double star to the west of the group provides a nice contrast. :)
