Messier 109 or M109 (also designated NGC 3992) is a barred spiral galaxy in the constellation Ursa Major. It has an apparent visual magnitude of 9.8 and its angular diameter is 7x4 arc-minutes. M109 lies at an estimated distance of 55 million light years. The Equinox 2000 coordinates are RA= 11h 57.6m, Dec= +53° 23´ which makes M109 best seen during the spring. The Messier Spring Star Chart shows the position of all Messier objects visible during that season.

The image above shows the uncropped view of M109 through the Takahashi E-180 Astrograph (North is up). The bright 2.43 magnitude star Phecda (Gamma Ursae Majoris) lies 0.7 degrees northwest of M109. A 3x enlargement of this image centered on M109 appears to the right.

This galaxy was discovered by P. Méchain in 1781. It is one of four barred spiral galaxies included in the Messier Catalog (M58, M91, M95, and M109).

According to Stoyan et al. (2010), the distance of M109 is 67.5 million light years and its diameter is 137,000 light years. Its estimated mass is 250 billion solar masses.

For more information, see the Messier Catalog as well as specific entries for M109 in Wikipedia and SEDS.

Messier's Description of M109

Méchain in his letter to Bernoulli, May 6, 1783)
`Page 265 No. 97 [M97]. A nebula near Beta in the Great Bear. Mr. Messier mentions, when indicating its position, two others, which I also have discovered and of which one is close to this one [M108], the other is situated close to Gamma in the Great Bear [this is M109], but I could not yet determine their positions.'

Messier added a position by hand which Owen Gingerich identified in 1953 as NGC 3992, which is now called M109)

Technical Details

AstroPixels Links

| Open Clusters | Globular Clusters | Diffuse Nebulae | Planetary Nebulae | Supernovae | Galaxies |
 | Messier Catalog Photo Gallery | Messier Catalog | Caldwell Catalog Photo Gallery | Caldwell Catalog | 
 | AstroPixels Photo Index |