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M 94
17 of 111

M 94

February 19, 2005
Spiral Galaxy M94 (NGC 4736), type Sb, in Canes Venatici

Right Ascension: 12 : 50.9 (h:m)
Declination: +41 : 07 (deg:m)
Distance: 14500 (kly)
Visual Brightness: 8.2 (mag)
Apparent Dimension: 7x3 (arc min)

Discovered by Pierre Méchain in 1781.

M94 was discovered by Pierre Méchain on March 22, 1781. Getting the report of his friend, Charles Messier observed it, determined its position and cataloged it on March 24, 1781.

Spiral galaxy M94 was classified Sab because of its extremely bright inner region (overexposed in our image). This bright circular disk is surrounded by a ring of active star-forming regions, traced by blue young star clusters in color images, which sharply separates it from a much less bright outer ring of an older yellowish stellar population. In the outskirts, this region however ends again in a ring with moderate star formation activity, so that M94 is one of the relatively rare galaxies in which two "waves" of stellar formation can be observed. In very long exposures, a further very faint ring, about 15 arc minutes across, becomes visible, a suggestion of which is visible in the DSSM image of M94, but see also the inset in the Hubble Atlas of Galaxies.

The distance of M94 is not yet well-determined (at least to the knowledge of the present author). Tully gives about 14 million light years, Burnham 20, Kenneth Glyn Jones 33 million light years.

De Vaucouleurs (1975) has listed M94 as a member of a nearby group or cloud of galaxies, the Canes Venatici I (CVn I) Cloud or M94 group, together with M64 and a number of fainter galaxies. This group is also noted by Schmidt and Boller (1992), but not listed in R. Brent Tully's Nearby Galaxies Catalog, who mixes up most members (but excluding e.g. M64) in one group with the members of Schmidt-Boller's NGC 4244 group.


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