M51: Whirlpool Galaxy

93f6375384c1dea4b97f868c2ffb0045.1824x0_q100_watermark_watermark_opacity-20_watermark_position-6_watermark_text-Copyright Giulio Ercolani
The Whirlpool Galaxy (also known as Messier 51aM51a, 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, but different methods yield distances between 15 and 35 million ly. 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, and the two galaxies may even be seen with binoculars. The Whirlpool Galaxy is also a popular target for professional astronomers, who study it to further understand galaxy structure (particularly structure associated with the spiral arms) and galaxy interactions.
In 2005 a supernova (SN 2005cs) was observed in the Whirlpool Galaxy, peaking at apparent magnitude14.
On 31 May 2011 a type II supernova, was detected in the Whirlpool Galaxy, peaking at magnitude 12.1. This supernova, designated SN 2011dh, showed a spectrum much bluer than average, with P Cygni like characteristics in its hydrogen-Balmer lines. Interestingly, the progenitor was probably a yellow supergiant and not a red or blue supergiant, which is unusual.

Imaging telescopes or lenses: Planewave 12.5 ” CDK Dell Kirkham Astrograph
Imaging cameras: SBIG STXL 6303
Mounts: Paramount PME
Software: Startools
Filters: Astrodon Blue, Astrodon Green, Astrodon Red, Astrodon Luminance
Dates: May 16, 2014, May 22, 2014, May 26, 2014, May 27, 2014
Astrodon Blue: 5×300″ bin 1×1
Astrodon Green: 5×300″ bin 1×1
Astrodon Luminance: 16×300″ bin 1×1
Astrodon Red: 5×300″ bin 1×1
Integration: 2.6 hours

Author: Giulio Ercolani
AstroPhotography of the day by SPONLI 6 Aug 2014