The Whirlpool Galaxy, Messier 51 or NGC 5194, is an interacting grand-design spiral galaxy with a Seyfert 2 active galactic nucleus in the constellation Canes Venatici. Recently it was estimated to be 23 ± 4 million light-years from the Milky Way. Messier 51 is one of the best known galaxies in the sky. The galaxy and its companion, NGC 5195, are easily observed by amateur astronomers. The Whirlpool Galaxy is also a popular target for professional astronomers, who study it to further understand galaxy structure and galaxy interactions.

Whirlpool Galaxy was discovered on October 13, 1773 by Charles Messier while hunting for objects that could confuse comet hunters, and was designated in his catalogue as M51. Its companion galaxy, NGC 5195, was discovered in 1781 by Pierre Méchain, although it was not known whether it was interacting or merely another galaxy passing at a distance. It was not until 1845 that William Parsons, employing a 72-inch (1.8 m) reflecting telescope at Birr Castle, Ireland, found the Whirlpool possessed a spiral structure, the first "nebula" to be known to have one. These "spiral nebulae" were not recognized as galaxies until Edwin Hubble was able to observe Cepheid variables in some of these spiral nebulae, which provided evidence that they were so far away that they must be entirely separate galaxies. [Source: Wikipedia]

The image was captured with the venerable Meade 12"LX200, using the Atik 383L+ mono at F7.16 (i.e. 2182mm FL). Astronomik's Luminance, Red, Green and Blue filters were used. Subs were taken at 1x1 bin, -10C, and 7 1/2 minutes each for Luminance and 5 minutes each for R, G and B.

Image 2016 --

Lum 450s: 82 subs (10.25 hr) on Apr 21st, Apr 22nd, Apr 24th, Apr 27th and Apr 30th.

Red 300s: 15 subs (1.25 hr) on Apr 21st, Apr 22nd, and Apr 27th.

Green 300s: 16 subs (1.33 hr) on Apr 21st, and Apr 22nd.

Blue 300s: 21 subs (1.75 hr) on Apr 21st, Apr 22nd, and Apr 27th.

Processing was done with PixInsight, following (for the most part) kayronjm's tutorial of Feb. 24th, 2013. Only L was used to develop the Luminance image. R, G and B were collected for the color mix. Narrow band filters were not used on this project. North is up, and this is a slight crop due to the misalignment accumulation from so many different filters and times.

I'm afraid the image is a bit over processed. In trying to minimize light pollution reflections, I also killed some of the faint nebulosity towards the subject's right side.