Bode's Nebula, or M81, is one of the brightest galaxies visible from in the night sky. It was first discovered by Johan Elert Bode in 1774. This nebula is from the spiral galaxy, and is from the constellation, Ursa Major. Spiral galaxies consist of flat, rotating disks that contain stars, dust, and gas. Most of the emission from infrared wavelengths originates from interstellar dust. There is also is central concentration of stars within the galaxy, and that is known as the bulge. M81 is located a proximately 10 degree northwest of Alpha Ursae Majoris, making it rather easy to locate in the night sky.
Bode's Nebula possesses right, symmetrical spiral arms and has numerous lanes of interstellar dust. The spiral arms consist of ongoing star formation and are brighter than the rest of the object due to the young, hot blue stars that inhabit them. The spiral arms have some lumpy areas because of the massive star clusters that are there. The bulge is incredibly bright due to the older, denser formation of stars that it consists of. M81 is gravitationally interacting with M82, which has consequently stripped some hydrogen gases from each galaxy resulting in the formation of filamentary gas structures in the M81 group. The distance to this object is estimated to be 12 million light years (O'Meara, 1998); we find a maximum angular size of 22 arcminutes, which corresponds to a linear size of 77,842 light years. The image above does not quite do Bode's Nebula justice. When combining the two mosaic images, a nonlinear transformation had to take place and the solar arms, consequently, appear much fainter than they truly are.
O'Meara, Stephen J. The Messier Objects. Cambridge: Cambridge University Press, 1998. 39-50. Web. 19 Apr. 2011.
Jenson, Joseph B. "Measuring Distances and Probing the Unresolved Stellar Populations of Galaxies Using Infrared Surface Brightness Fluctuations." The Astrophysical Journal 583.2 Feb. (2003): 712-26. Google Scholar. Web. 19 Apr. 2011.
|Right Ascension (J2000)||9:55:36|
|Filters used||11, 12|
|Exposure time per filter||11 (120s); 12 (120s)|
|Date observed||March 31, 2011 UT|