Messier 81 (NGC 3031) - Bode's Nebula
M81 is a spiral galaxy with the morphological classification of SA(s)ab I-II. This means that this galaxy is classified as a non-barred spiral type [SA], with an "s" shaped structure [s], fairly tightly wound spiral arms [ab] that are moderately well developed [I-II].
M81 is located in the Messier 81 Galaxy group, the center of which is located about 10 million light years away. The Messier 81 Galaxy Group is the second closest galaxy group to our own Local Group. The nearest to us is the Sculptor Group, only 8 million light years away. The absolute magnitude of M81 is estimated to be -20.8, a luminosity of 17 billion suns.
M81 was discovered by J.E. Bode of Berlin in December 1774. Charles Messier added this object to his now famous catalogue in February 1781. This object is also commonly referred to as "Bode's Nebula" after its discoverer. It was not until the 20th Century that astronomers realized that the myriad of faint "nebulosity" surrounding us are actually galaxies separate and apart from our own.
For more on Messier 81 see: http://www.seds.org/messier/m/m081.html
December 20, 2004
LRGB combination of six 6 minute sub exposures per channel
Vallecito County Park, Anza-Borrego Desert, San Diego County, California
Optics - Takahashi MT-200 with Takahashi f/4.8 reducer,
Mount - Astro-Physics 1200 GTO
Camera - SBIG ST-2000XM