Object Type: Spiral Galaxy (Sc)
Constellation: Canes Venatici
Magnitude: 8.4
Size: 11' x 7'

M51 was discovered by Charles Messier in 1773. It was the first galaxy in which spiral structure was seen, as described by Lord Rosse in 1845. The spiral structure can be visually detected in telescopes as small as four inches in aperture under excellent conditions, although typically an eight-inch telescope is required for the spiral structure to be seen distinctly. M51 actually consists of two interacting galaxies; the main spiral galaxy is designated NGC 5194, and the smaller galaxy NGC 5195. M51 is estimated to be 37 million light-years from our solar system.

Equipment: Meade 14" LX200R/ST-10XME/Astro-Physics CCDT67 telecompressor/Astrodon LRGB filters/Paramount ME
F-ratio: f/6.5
Exposures: LRGB:  L 8 x 5 minutes, binned 2x2: R 8 x 5 minutes: G 8 x 5 minutes: B 8 x 5 minutes: RGB binned 3x3
Date: March 17, 2007
Location: Landers, California, USA
Technical Notes: Individual exposures were obtained using CCDAutoPilot2 and then sigma combined. The RGB image was created in Registar 1.0. A high-pass filter of 4 pixels was applied to the bright portions of the luminance image.