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Astr112 Photography Projects, Spring 2006

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M101, Luke Emanuelson


The spiral galaxy M101 is one of the Messier objects. Originally discovered and categorized by Charles Messier to be an object of little interest and not to be mistaken for the more interesting comets which he was seeking, M101 is anything but uninteresting. As a beautiful spiral galaxy, it is categorized as an Sc type spiral galaxy due to its smaller bulge, large clumpy arms, and lack of bar. Within in this galaxy there are many massive star-forming HII regions. At about 22 million light years away, it is about 7 times as far from earth as the nearest spiral galaxy, Andromeda. In addition, at about 24 kpc in diameter, its diameter is about 8 kpc smaller than that our own Milky Way.

A number of the bright HII regions (reddish) can be seen above and to the right of the bulge. In these regions, clouds of hydrogen are glowing in the light of new formed stars. In the center is the bulge. It contains the oldest, most stable stars, most of whom are still on the main sequence. Because it is the oldest, most of the high-mass, high-luminosity (blue) stars have since gone off the main sequence and become white dwarfs and neutron stars. This leaves the mid to low mass stars (yellowish) and thus their yellowish light dominates the image that we see with out eyes.






Right Ascension (J2000) 14:03:12.8
Declination (J2000) +54:21:36
Filters used blue(B), green(V), red(R), and clear(C)
Exposure time per filter 5x60 seconds in C, 300 seconds in BVR
Date observed

March 13, 2006 (RV)
March 15, 2006 (B)
March 30, 2006 (C)