OBJECT = M104
TELESCOPE = 17.5 inch f3.23
CAMERA = ST7-E
OBSERVER = Rusty Fletcher
LOCATION = Seguin Outdoor Learning Center
DATE (Yr-Mo-Dy) = 2005-01-08
TIME (UT) = 11:07:37
TOTAL EXPOSURE = 950 sec.
IMAGES STACKED = 19
Spiral Galaxy M104 (NGC 4594), type Sa, in Virgo
The Sombrero Galaxy
M104 is numerically the first object of the catalog which was not included in Messier's originally published catalog. However, Messier added it by hand in his personal copy on 11th May 1781 as a "very faint nebula." It was Flammarion who found that its position coincided with Herschel's 43 H I, which is the Sombrero galaxy, and added it to the official Messier list.
This brilliant galaxy was named the Sombrero Galaxy because of its appearance. According to de Vaucouleurs, we view it from just 6 degrees south of its equatorial plane, which is outlined by a rather thick dark rim of obscuring dust. This dust lane was probably the first discovered, by William Herschel in his great reflector.
This galaxy is of type Sa-Sb, with both a big bright core, and as one can see in shorter exposures, also well-defined spiral arms. It also has an unusually pronounced bulge with an extended and richly populated globular cluster system - several hundred can be counted in long exposures from big telescopes.
This galaxy was the first one with a large redshift found, by V.M. Slipher at Lowell Observatory in 1912. Its redshift corresponds to a recession velocity of about 1,000 km/sec (it is caused by the Hubble effect, i.e. the cosmic expansion). This was too fast for the Sombrero to be an object in our Milky Way galaxy. Slipher also detected the galaxy's (then the nebula's) rotation.
Right ascension 12 : 37.3 (hours : minutes)
Declination -11 : 21 (degrees : minutes)
Distance 50,000,000 light-years
Visual magnitude 8.7
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