Full-resolution version

Object Type:  Spiral Galaxy (Sc)
Constellation:  Triangulum
Magnitude:  5.7
Size:  62' x 39'

The third largest member of our Local Group of galaxies after M31 and the Milky Way, M33 is located at a distance of 3 million light-years, and is generally considered the most distant object visible to the naked eye. Despite its large apparent size, its low surface brightness makes it a challenging naked-eye object, requiring very transparent skies to be seen. M33 contains numerous H-II regions (emission nebulae), many of which are visible on this image. NGC 604, one of the largest H-II regions in the known universe at 1500 light-years in diameter (50 times the diameter of the Orion Nebula), is the bright red nebulosity to the upper right of the galactic nucleus. The next-largest H-II region is NGC 595, located below and slightly to the right of the galactic nucleus.

Equipment: Vixen 102-ED/ST-10XME/Astrodon LRGB filters/Losmandy G-11/Gemini/Paramount ME
F-ratio: f/6.5
Exposure: RGB: R 13 x 20 minutes: G 12 x 20 minutes: B 12 x 20 minutes
Date: October 30 and November 4, 2010
Location: Landers and Borrego Springs, California, USA