M31

From South Dublin Astronomical Society

M31
Type	Spiral Galaxy SB??
NGC	NGC 224
Constellation	Andromeda
Right Ascension	0h 42.7m
Declination	+41° 16’
Magnitude	3.4
Size	178 x 63 arc min.
Image:M31 messier image.jpg

On clear nights, far from the glare of lights, you may spot a dim elongated smudge of light a short hop from the brightish star Beta Andromedae. Long exposure photographs reveal the object as a giant “star city” of over 100 billion suns that we know as M31, the Andromeda Galaxy. Binoculars will let you trace the cigar-shaped glow which brightens a little towards the central core. Because M31 is tilted to our line of sight we cannot really appreciate the full majesty of this object but one aspect you should look for is how the light of the galaxy ends abruptly towards the northern edge. This is because of dark dust lanes in the periphery of the disk. Larger glasses may be needed to spot two companions, M32 and M110 (both ellipticals). M32 is a tiny spot of light slightly west of south of the nucleus of M31. Eighth-magnitude M110 is a grey ellipse to the north. It lies twice as far again from the parent as M32.