Discovered in 1773, M51 (& NGC5195) is one of the most well known galaxies in the sky and is a good example of a face-on spiral galaxy.
Its distance is approximately 23 million light years.

Just as M81 and M82, M51 and NGC 5195 (bottom part) are also gravitationally interacting galaxies.
Sometimes M51 is used to refer to both galaxies, in which case the individual galaxies are referred to as M51A (NGC5194) and M51B (NGC5195).

In 2005 as well as 2011 a supernova was observed in the Whirlpool Galaxy. These events helped to derive a more correct distance of 23 Mly as it was previously estimated to be around 37 Mly

Other versions

Previous/older images:

Mar 07, 2010 – ST-8300M (10″ Newt. 2h20m)

Mar 12, 2007 – Canon 350D (8″ GSO f4 Newt. 1h30m)

Image data

Object info
Name M51 – The Whirlpool Galaxy
Type Spiral galaxy
Constellation Canes Venatici
Right ascension 13h 29m 52s
Declination +47° 11′ 43″
Distance 23 Mly
Other designations M51A, NGC5194, M51B, NGC5195, UGC8493, Arp 85
Image info
Image date Mar. 22, 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, ImagesPlus, PixInsight LE, Photoshop CS4
Processing CCDOPS was used for focussing. Image Acquisition was done using CCDSoft.
All separate frames were calibrated, aligned and stacked in ImagesPlus.
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.