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M 99 - NGC 4254 - Coma Pinwheel Galaxy
Coma Berenices
Penryn, California
March 2004/2009 (lum)
FS-128  (ag, ST-4)
ST-10XME LR(s)GB 10 minutes luminance, 15 minutes each color

 M99, although situated in the constellation Coma Berenices, is one of the bright spiral members of the Virgo Cluster of galaxies. It is of type Sc, rotates clockwise (unlike the nearby spiral M100), and is unusually asymmetric, the nucleus shifted to the upper end of our picture. The present author speculates that this asymmetry could be due to semi-recent encounters with other members of the Virgo Cluster, a hypothesis which may get seconded by the fact that its recession velocity is quite high for a Virgo Cluster member: 2324 km/sec according to the Sky Catalog 2000.0, the highest recession velocity measured for a Messier galaxy (and thus a Messier object at all). This means that it is moving through the Virgo Cluster with a high proper (or peculiar) velocity of at least about 1200 km/sec, by chance in a direction pointing away from us.  (