Contains:  M 101, NGC 5457
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M101 Pinwheel Galaxy in HaLRGB (Red Zone), 





    
        

            Douglas J Struble
M101 Pinwheel Galaxy in HaLRGB (Red Zone)

M101 Pinwheel Galaxy in HaLRGB (Red Zone)

Technical card

Resolution: 3138x2514

Dates:Feb. 12, 2018April 6, 2018April 7, 2018April 8, 2018

Frames:
Astrnomik CLS-CCD: 978x60" -20C bin 1x1
Astrodon Blue Tru-Balance E-Series Gen 2: 161x60" -20C bin 1x1
Astrodon Green Tru-Balance E-Series Gen 2: 161x60" -20C bin 1x1
Astrodon Ha 5nm: 7x240" (gain: 139.00) -20C bin 1x1
Astrodon Red Tru-Balance E-Series Gen 2: 162x60" -20C bin 1x1

Integration: 24.8 hours

Darks: ~50

Flats: ~50

Bias: ~250

Avg. Moon age: 22.68 days

Avg. Moon phase: 45.78%

Bortle Dark-Sky Scale: 6.00

Astrometry.net job: 2041944

RA center: 210.740 degrees

DEC center: 54.382 degrees

Pixel scale: 0.649 arcsec/pixel

Orientation: 31.566 degrees

Field radius: 0.363 degrees

Locations: Backyard Red Zone Observatory, Taylor, MI, Michigan, United States

Data source: Unknown

Description

This one is a tough one to work on; especially in my heavy light polluted red zone I am in. I started this a couple months ago, however my Astro-Physics Mach1 had to go into warranty repair and was gone for about a month. I finally finished it off after it got back.

M101 is a large face-on spiral galaxy located 22 million light-years away in the constellation of Ursa Major. At magnitude +7.9, it can be glimpsed in binoculars or small telescopes from dark sites. However, this galaxy suffers from low surface brightness and in bad seeing conditions or light polluted areas is sometimes difficult to spot even with 200mm (8-inch) scopes. M101 is best seen from the Northern Hemisphere during the months of March, April and May.

M101 is also known as the Pinwheel galaxy and was discovered by Pierre Méchain on March 27, 1781. He described it as "nebula without star, very obscure and pretty large, 6' to 7' in diameter, between the left hand of Boötes and the tail of the great Bear." He communicated this to Charles Messier, who verified its position and then included it in his catalogue as one of the final entries.

Locating the part of sky where M101 is positioned is easy, since it's close to the handle of the bowl that forms the Plough or Big Dipper asterism of Ursa Major. The Pinwheel galaxy is located at one corner of an equatorial triangle formed with second magnitude stars Mizar (ζ UMa - mag. +2.2) and Alkaid (η UMa - mag. +1.8). M101 is 5.5 degrees east of Mizar (the celebrated naked eye double star) and 5.5 degrees northeast of Alkaid.

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dugstruble
Douglas J Struble
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M101 Pinwheel Galaxy in HaLRGB (Red Zone), 





    
        

            Douglas J Struble