M101 - The Pinwheel in Ursa Major (Monty Chandler)

M101 - The Pinwheel in Ursa Major

Link: https://montychandler.smugmug.com/Astrophotography/The-Heavans/i-hj6dckp/A

M101 - The Pinwheel Galaxy - is a face-on spiral galaxy 21 million light-years away from Earth in the constellation Ursa Major (Big Dipper). Located just west of the last star in the handle.

M101 is a large galaxy containing approx 1 trillion stars, with a diameter of 170,000 light-years. By comparison, the Milky Way has a diameter of between 100,000 and 120,000 light-years.

M101 has a high population of H II 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. H II regions are ionized by large numbers of extremely bright and hot young stars; those in M101 are capable of creating hot superbubbles.

In a 1990 study, 1,264 H II regions were cataloged in the galaxy. Three are prominent enough to receive New General Catalogue numbers—NGC 5461, NGC 5462, and NGC 5471.

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 that can be detected in ultraviolet images.

M101 has six prominent companion galaxies: NGC 5204, NGC 5474, NGC 5477, NGC 5585, UGC 8837 and UGC 9405.

As stated above, the gravitational interaction between it and its satellites may have spawned its grand design pattern.

There are at least 4 different galaxies resolved within this image.  M101 is the largest and closest. NGC5474 is at the lower left. NGC5477 is above the bottom arm of M101 and appears equally distant between the two yellow stars. NGC5473 is at the far left of the image in the middle.

Image acquisition via APT using a SW Esprit120ED, ASI2600MC Pro camera, & EQ6r Pro mount from my backyard in the hills of western NC.

Original
Final
B

B

Description: Additional sessions added in 2024 - total of 397 300s exposures - 33 hours

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Status	Advanced success
Started	...
Astrometry.net job	9757778
PixInsight job	R8EPIPMW3PVRCDFP1UFHZQRIMCYQCSKB
PixInsight queue size	n/a
PixInsight stage	TASK_LOG

RA (center)	14h03m44s.606
RA (top/left)	14h09m30s.731
RA (top/right)	14h01m45s.149
RA (bottom/right)	13h57m58s.908
RA (bottom/left)	14h05m39s.732

Dec (center)	+54°17′33″.73
Dec (top/left)	+54°17′49″.10
Dec (top/right)	+55°04′58″.65
Dec (bottom/right)	+54°16′17″.93
Dec (bottom/left)	+53°29′59″.50

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