Image centered on Ra 12 : 36.8 (h:m)
Dec +13 : 10 (deg:m)
M 90
Spiral Galaxy M90 (NGC 4569), type Sb, in Virgo
Information ( From the SEDS website )
Discovered 1781 by Charles
Messier.
Spiral galaxy M90 is one of the eight galaxies found and cataloged on March 18,
1781 by Charles Messier in the Coma-Virgo region, in addition to M92, the
Hercules globular, to round up score to nine newly cataloged objects on that
day.
M90 is one of the larger (9.5x4.5') spirals in the Virgo Cluster of Galaxies. It
has tightly wounded, smooth bright spiral arms, which appear to be completely
"fossil", meaning that currently no star formation appears to take place, with
the only exception of the inner disk region, near the darker dust lanes. J.D.
Wray speculates that this galaxy may be on the way to evolve into a state
similar to M64, and then into a lenticular (S0) system.
Although M90 is conspicuous and big, Holmberg has derived quite a low value for
its mass, which implies that this may be a very low density galaxy.
As it is approaching us at 383 km/sec, it must have the very high peculiar
velocity of nearly 1500 km/sec through the Virgo cluster into the direction
pointing to us, and possibly is just in process of escaping the cluster; some
sources have speculated it may already have left the cluster and be now a
considerable distance nearer to us. Only one Messier galaxy is faster in
approaching us, M86.
Optics and Exposure data
Telescope, Parks Optical 10 inch newtonian @ F5 and a Televue Coma Corrector which increases the focal ratio slightly to an F5.5 equaling a focal length of roughly 1300 mm .
Mount, Losmandy G11 with Gemini control electronics
Imager, Starlite-Xpress SXV-h9 using Astronomiks RGB optical filters.
60 minutes luminance using 2 minute subexposures.
RGB imaged with an 800mm fl Vixen Newtonian
Images acquired with Astroart and aligned then combined in Maxim Dl. Final RGB composite processed with Photoshop Cs
Images acquired from my backyard - " Dirt Clod Observatory" in Antelope California
