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M101: Pinwheel Galaxy in Ursa Major

RA = 14 hrs 03 min; Dec = 54 deg 21 min.

Date & Site:

Imaged from 4/17 - 4/18/2015;Little Blair Valley, Anza Borrego Desert, CA

Conditions: mild winds; 60 degrees; below average seeing; clear and transparent


Telescope: TEC 140 Refractor f/7 980mm fl

Mount: AP 1100 GOTO CP3
Camera: ST-10XME; CFW10; Internal auto guiding


Exposures: 3.5 hrs (10 min subs) of Lum and 1 hr each each of RGB (10 min subs) for total of 6.5 hours

M101 is noted for its high population of HII regions, many of which are very large and bright. H II regions usually accompany the enormous clouds of high density molecular hydrogen gas contracting under their own gravitational force where stars form. M101 is asymmetrical due to the tidal forces from interactions with its companion galaxies. These gravitational interactions compress interstellar hydrogen gas, which then triggers strong star formation activity in M101's spiral arms shown in this image as redish blobs (credit: Wikipedia)

Field of View =52x 35 arc minutes

21 million light years away

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