This fine barred spiral galaxy located in the Coma Berenices was once a "missing object" in Charles Messier´s object list.First published by William Herschel in 1784 as NGC4548,it was realized by W.C.Williams in1969 that this was a mistake by Messier,who had discovered it first in 1781.
Its a Hubble-spiral of type SBb(rs9) with an apparent diameter of 5x4 arc minutes and a magnitude of 10.2mag.Although it belongs to the Virgo Cluster of Galaxies it is situated in the constellation of Coma Berenices at a real distance of about 60 million light years with a diameter of 83.000 light years.
Very little rates of star formation take place in M91 compared with other equal typed galaxies
RA.: 12h 35m 26,4s
Decl.: +14° 29′ 47″
LRGB image with L = 24x1200s, RGB = 9x1200s each,a total of 17.0 hours
80cm f/7 AstroOptik Keller corrected cassegrain FLI Proline 16803 Astrodon LRGB GenII filters Prompt 7 CTIO/UNC Chile,remote controlled
image processing: Bernd Flach-Wilken
here you see 77% of the FOV with the fine spiral galaxy M91 in the middle.Click here for a look at full resolution.
here is a more detailed look to M91:
for a high-resolution-look trough the HST click here