Andromeda, known as "the Great Galaxy", or M31, is 2.2 million light years away, yet it can be seen with the unaided eye. It is the furthest, and by far, the largest object in the universe we can see without a telescope. From the northern half of the Earth it is the only object we can see without assistance that is not inside our own galaxy, the Milky Way. The light we see now from Andromeda left there just after the first humans appeared on Earth.The Andromeda Galaxy is referred to as a sister to our own galaxy, the Milky Way. Each is an enormous disk, approximately 100,000 light years wide, made up of hundreds of billions of suns. Each is a spiral galaxy, in the shape of a giant pinwheel, with arms that appear to unwind from a central core. Though separated by great distance, on a cosmic scale both reside in the same neighborhood. They are the two largest members of a group of approximately twenty two galaxies named "the Local Group". Each has two smaller companion or satellite galaxies "close" to it (the companion galaxies of the Milky Way are named the Large and Small Magellanic Clouds, visible from only the southern half of the Earth). Each rotates slowly around its own core with its spiral arms going all the way around once every 1/4 billion years. The two rotate in complimentary directions, one clockwise and the other counterclockwise. Each is aligned so that it presents itself to the other at almost exactly the same angle.
The Milky Way from Andromeda is thought to look almost the same as Andromeda appears to us. In a sense, to look at Andromeda is to see ourselves. There are so many similarities that, according to one theory the two galaxies formed at about the same time, from two adjacent whirlpools of primordial gas.
We see Andromeda, and Andromeda "sees" us, from almost an edge-on view, not full face. That makes it appear to have an oval shape, rather than its actual circular shape. It can be seen with the unaided eye from dark locations as a fuzzy patch of light. With binoculars it looks like a hazy oval, with a brighter core and dim outer regions. Sweep across it repeatedly with binoculars to see its outer regions. With a low power eyepiece on a telescope, its oval shaped glow is distinct.
Andromeda is visible from the northern half of the Earth. It is best seen beginning in late summer and throughout the autumn. It is found in the constellation that bears its name - Andromeda. (See beautiful time-exposure Photo of Andromeda from Jason Ware's home page). The easiest way to find it is to face north and locate the constellation Cassiopeia, which looks like a giant and slightly squashed letter "M" in the sky. Using the left half of the "M" as an imaginary arrowhead, go about 1 1/2 fist widths (the width of your clenched fist held up to the sky at arm’s length) in the direction the arrowhead points in. Scan this area with binoculars to identify the fuzzy elongated glow of light that is Andromeda.
When you find it, understand that you are looking at one of nature’s grandest creations - a distant and beautiful, "island universe" of enormous proportions, surrounded by the void of intergalactic space, far more remote than the stars of our home galaxy you see around it.
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