This image is one of the most famous of spiral galaxies. M31 is one of the farthest objects that can be see with the unaided eye — it is 2.3 million light years away! Under dark skies it appears as a hazy area in the constellation Andromeda. A pair of modest binoculars will make the galaxy more appearant, with some of the structure discernable. M32, a dwarf elliptical galaxy and companion to M31, is also seen with binoculars. The first written report of M31’s position is from Al-Sufi, who was a Persian astronomer in the tenth century.
Numerous dust lanes can be seen as fine dark filaments encircling the central core of the galaxy. Often seen in larger aperture instruments, they are not frequently seen by small – moderate aperture telescopes such as those used to take this image. Also in the image are the two irregular dust “lanes” of M110. Knots of newly formed stars are seen as areas of white-blue patches in the outer arms of M31.
This image has been processed to show the outer regions of the galactic disk and the tidal bridge between M31 and M110.