Contains: NGC 5485, NGC 5474, NGC 5473, M 101, NGC 5457, NGC 5422
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M101 - The Pinwheel Galaxy

Technical card

Resolution: 4920x3300

Dates: April 15, 2017

Frames: 59x90" ISO1600

Integration: 1.5 hours

Darks: ~10

Avg. Moon age: 18.62 days

Avg. Moon phase: 84.09%

Bortle Dark-Sky Scale: 5.00

Temperature: 7.00 job: 1544683

RA center: 210.751 degrees

DEC center: 54.351 degrees

Pixel scale: 1.837 arcsec/pixel

Orientation: -178.898 degrees

Field radius: 1.511 degrees

Locations: Happy Frog Observatory, Monroe, Connecticut, United States


Messier 101 - The Pinwheel Galaxy (a.k.a. NGC 5457) is a face-on spiral galaxy distanced 21 million light-years away from earth in the constellation Ursa Major. M101 is a large galaxy comparable in size to the Milky Way with a diameter of 170,000 light-years. The galaxy 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 that can be detected in ultraviolet images. On August 24, 2011, a Type Ia supernova, SN 2011fe, was discovered in M101. The supernova was visual magnitude 17.2 at discovery and reached magnitude 9.9 at its peak. Also M101 has several companion galaxies gravitationally linked to it. (source: wikipedia).

I was lucky lucky to get this last Saturday when the sky unexpectedly cleared up enough to get 1.5 hrs of decent exposures. I think I can do better with this object with more exposures, however, that will have to wait as I have too many other thing to capture on limited clear nights in the Northeast. The weather has been awful since Saturday and it does not seem to be getting any better anytime soon. I used the Synthetic Flat-Layer removal method described by Trevor Jones from AstroBackyard to cleanup the gradients this time as it produced the best results.

BTW this object number 70 on my Messier catalog. Enjoy.



Kurt Zeppetello

Sky plot

Sky plot


M101 - The Pinwheel Galaxy, Kurt Zeppetello