M33 - The Triangulum Galaxy

Designations:	M33, Triangulum Galaxy, Pinwheel Galaxy, NGC 598
Object Type:	Spiral Galaxy
Constellation:	Triangulum
RA:	1 hr 33.9 min	Dec:	+30° 39 min
Magnitude:	5.7 Surface Brightness 14.2	Size:	71 X 42 arcminutes
Distance:	2.3 million light years
Discoverer:	Messier, 1764

In long-exposure photographs M33, another member of our Local Group of galaxies, looks like an enormous spiral with innumerable suns clinging to wildly spinning arms. But with a diameter of 50,000 light years, you could easily fit three M33's in the disk of M31. In fact, M33 may be a satellite galaxy of M31, orbiting it just as the moon does the earth. The Andromeda Galaxy is also about 15 times more massive than M33, which is about two times smaller and seven times less massive than our Milky Way. As seen from an imaginary planet in the Pinwheel Galaxy, M31 would be am impressive sight - an oblique swarm of faintly glittering suns stretching 6 degrees in that hypothetical sky. Regardless of its true size, the Pinwheel is a great sight from earth. It has long been a naked-eye challenge for amateur astronomers. While some find it easily visible to the naked eye or in binoculars, others cannot see it at all. The problem lies in the galaxy's low surface brightness. Although the total magnitude of M33 is the same as a 6th magnitude star, the galaxy's light is spread over an area of sky larger than two full moon diameters, making it appear dim. A dark sky, a steady atmosphere, and good vision are required to see M33 with or without optical aid. Its ease of visibility is, as Walter Scott Houston often stated, a barometer for the clarity of one's observing site. The galaxy is completely washed out in urban skies and can be disappointingly dim from suburban locations even through large-aperature telescopes! Try to see it, though, without optical aid, because M33 is one of the farthest objects visible to the naked eye.

Telescope:	TMB 152 APO Refractor
Focal Length:	961mm (1201 * 0.8x reducer)
Mount:	Takahashi NJP 160
Camera	SBIG ST10XME
Guider:	SBIG ST402ME
Exposures:	10 10-minute exposures (Luminance) and 3 10-minute exposures for each color (red, green, blue) Total = 130 minutes
Location:	Cicero, IN
Software:	CCDSoft for image acquisition, processed with CCDStack and Photoshop CS2