Tuesday, February 23, 2010

M82 - The Cigar Galaxy

Among the most popular objects to observe in the northern hemisphere are the 110 Messier objects, named after French comet hunter Charles Messier (1730-1817).  Messier compiled his list of objects mostly to avoid mistaking them for comets in his routine searches.  Ultimately he discovered 20 comets, 13 of which were original discoveries.  While not many amateurs are familiar with any of the comets he discovered, most folks have at least looked at a few of the objects in his catalogue.  Objects such as the Andromeda Galaxy (M31) and the Great Orion Nebula (M42) are among the most famous.  For many amateur astronomers, observing all 110 objects is a rite of passage.  While I have observed the entire catalogue, I still return frequently to many of the objects.

Tonight, with a moon that is 73% illuminated, I decided to have a look at M82, also known as the Cigar Galaxy.  Now observing galaxies under moonlight is not exactly optimal, however, after a few days of cloudy weather I was so photon deprived that even the moonlight could not deter my enthusiasm.  I had planned a sketch of mars, but when I took a look at the red planet, there were not many surface features visible, and what was visible was very difficult to observe due to the unstable atmosphere. While planetary observing suffers greatly from atmospheric turbulence, viewing of deep sky objects, such as galaxies, is much less affected.  The reason for this is that galaxies are low contrast, have low surface brightness and generally lack the fine detail that can be obscured in poor seeing conditions. 

I aimed the scope at M82 and after just a few minutes decided to make a quick sketch.  M82 is a remarkable galaxy in the constellation Ursa Major.  It has been studied extensively, and the picture to the left is a composite image made from the Hubble, Spitzer, and Chandra observatories.  It reveals the galaxy in visible wavelengths (the Hubble camera), as well as X-Ray (Chandra) and the infrared (Spitzer). 

Naturally, one does not see all that fantastic color at the telescope eyepiece, rather, one sees an elongateed smudge with some mottling, some bright regions, and a dust lane.  The picture to the right is a little closer to what one sees, particularly when knowing what to look for and using one's "averted imagination."  Below is my sketch of the galaxy, which you can see is reversed left-right from the photo.  I made the sketch with black pencil on white paper (a negative image), then scanned and inverted the image to provide a positive image. In other words, the sketch now appears as in the eyepiece:

Instrument: TEC 140
Eyepiece: 8mm (123X)
Time of sketch 0330 UT Feb. 24, 2010 (8:30 MST)

RA: 9h 55.8m
D: +69 deg. 41 min.

Distance: 12 million light years
Magnitude: 8.4     Size: 9 x 4 arcminutes

No comments:

Post a Comment