Messier 101, also known as the Pinwheel Galaxy (NGC 5457) is a face-on spiral galaxy that can be found in the constellation Ursa Major at 21 million light years from Earth.
With a diameter of approximately 170.000 light years, this galaxy is almost twice as large as our own Milky Way.

This galaxy features some huge and extremely bright H II regions in which stars are being formed, these can be seen as “blobs of nebulae” in the image.
A supernova was discovered on August 24, 2011 being the 4th supernova recorded in M101.

M101 is the brightest galaxy of a small group which consists of approx. 9 galaxies, named the M101 Group.
It is however not an easy visual target as it has a rather low surface brightness.

Other versions

Previous/older images:

Mar 19, 2009 – Canon 20D (10″ Newt. 1h56m)

Image data

Object info
Name M101 – The Pinwheel Galaxy
Type Spiral galaxy
Constellation Ursa Major
Right ascension 14h 03m 13s
Declination +54° 20′ 57″
Distance 21 Mly
Other designations NGC5457, UGC8981, PGC50063, Arp 26
Image info
Image date Mar. 25, 2012
Light frames 8x 4 min. RGB (each) unbinned, 16x 4 min. UHC-S unbinned (Luminance)
Total integration 2h 40m
Dark frames 10x
Flat frames 10x p. filter unbinned. Created with an A3 size Posterpoweruk flatfield panel
Bias frames 10x
Software used CCDOps, CCDSoft, Maxim DL, Photoshop CS4
Processing CCDOPS was used for focussing. Image Acquisition was done using CCDSoft.
All separate frames were calibrated, aligned and stacked in MaxIm DL5 Pro.
Photoshop CS4 was used for further processing – curves adjustment, levels adjustment, etc.
Noel Carboni’s toolset was used as well (Local Contrast Enhancement, Deep Space Noise Reduction)
(L)RGB combine was done in Photoshop.
Equipment info
Telescope Orion Optics SPX 10″ Newton
Corrector Televue 2″ Paracorr coma corrector (FL: 1.380mm f/5.43)
Mount Losmandy G-11 Gemini
Camera SBIG ST-8300M
Guide camera Atik 1HS Mono
Guide scope Celestron 60/700 Achromat
Autoguide software PHD Guiding
Filters Baader 2″ RGB + IDAS LPS-P2
Location Landgraaf, The Netherlands
Image comments

Distance from Paracorr to CCD is not correct.