M104 - Sombrero Galaxy




About this image.

Discovered by Pierre Méchain in 1781.

M104 is numerically the first object of the catalog which was not included in Messier's originally published catalog. However, Charles Messier added it by hand to his personal copy on May 11, 1781, and described it as a "very faint nebula." It was Camille Flammarion who found that its position coincided with Herschel's H I.43, which is the Sombrero Galaxy (NGC 4594), and added it to the official Messier list in 1921. This object is also mentioned by Pierre Méchain as his discovery in his letter of May 6, 1783. William Herschel found this object independently on May 9, 1784.

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.

Equipment

Telescope:                 12.5" Ritchey Chretien by RC Optical Systems
Mount:                      Paramount ME by Software Bisque
Instrument:               STL11000M CCD Camera by SBIG with AOL

Exposure:                  LRGB 195:60:60:60 minutes
Capture Software:      CCDSoft, CCDAutopilot
Processing:               Maxim DL, CCDStack, Photoshop CS2 

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