MESSIER 51 

SPIRAL GALAXY IN CANES VENATICI (THE HUNTING DOGS)

 (Image Centred at ra 13h:22m / dec +47:12)

CLICK THE IMAGE FOR A HIGHER RESOLUTION VIEW

Image data acquired by Jim Misti,   Arizona, USA. Image processing by Sergio Eguivar

DATA

Type: Spiral Galaxy

Apparent Magnitude:8.4

Apparent diameter: 11 x 7 arc minutes 

Distance: 27 Million light years

IMAGE INFORMATION

Optics: Ritchey-Chretien 32" f 7.2 Telescope

CAMERA: SBIG STL 11000  

SKY CONDITIONS: Dark Skies

EXPOSURES: LRGB (75,25,25,25)

OBJECT DESCRIPTION AND IMAGE SESSION

Although visible just a few degrees above the horizon from the Southern Hemisphere, Messier 51 is nearly impossible to image from Buenos Aires. So this time I took the chance to process the raw files that Jim Misti  kindly offers for processing. Once more, thanks Jim for this generous initiative!!

M51 was one of Charles Messier's original discoveries on October 13, 1773, while observing a comet. He described as a "very faint nebula, without stars" which is difficult to see. Its companion, M51B (NGC 5195), was discovered on March 21, 1781 by his friend Pierre Francois Andre Méchain.

According to our present understanding, the pronounced spiral structure is a result of M51's current encounter with its neighbor, M51B (aka NGC 5195). Due to this interaction, the gas in the galaxy was disturbed and compressed in some regions, resulting in the formation of new young stars. As is common in galactic encounters, spiral structure is preferably induced in the more massive galaxy. Halton Arp has included M51 as No. 85 in his Catalogue of Peculiar Galaxies as "Spiral with Large High-Surface-Brightness Companion".