On a clear dark night, you may find yourself looking up at the sky in wonder. You may be curious as to what is the most distant object you can see with your naked eyes. Is it Saturn at 750 million miles (1.2 billion kilometers) away? Is it the Milky Way, stretching across the sky from north to south at approximately 25,000 light years’ distance? Or is there something even further away that may be glimpsed with nothing but your good old naked eyes?
The Andromeda Galaxy located near the Square of Pegasus can be seen with your naked eye from a fairly dark suburban sky, and lies around 2.5 million light years away. It is one of the most distant objects that you can see with no optical aid. By finding the large square that forms the constellation Pegasus and finding the “W” that makes up Cassiopeia, you can find the Andromeda Galaxy fairly easily. It appears as a dim smudge of light that is much larger than a star.
Also known as the Great Galaxy in Andromeda, or as Messier object #31, the Andromeda Galaxy is indeed large! It’s the closest major galaxy to the Milky Way, and is just over twice as large as our own galaxy. If it were brighter, it would appear as wide as 5 or 6 full moons in the night sky. M31 is a large, spiral galaxy similar to the Milky Way, but its orientation towards us makes the spiral arms a little trickier to distinguish. It’s also worth noting that M31 is moving towards the Milky Way. In fact, in about 4 billion years, it will collide with the Milky Way.
Using binoculars will help you to see more than just the bright center of M31, but to see the full width of the Andromeda Galaxy, you will need to use a telescope. While viewing M31 with a larger telescope, you may even begin to make out some of the spiral structures and dust lanes, as well as two smaller satellite galaxies, similar to the Magellanic Clouds of the Milky Way.
When looking near the center of M31 with a telescope, you may see what looks like a fuzzy star nearby. That fuzzy star is M32, one of M31’s satellite galaxies. It is a dwarf elliptical galaxy, and is only about 6,500 light years across. It lies slightly farther away than M31 at around 2.6 million light years away. M32 is too small to see with binoculars, so you will need a telescope. Try and see how much magnification you can use to see M32.
M110 is located on the opposite side of M31, and is slightly more dim. It’s slightly larger than M32, at around 17,000 light years across. M110 is also a dwarf elliptical galaxy. It will appear as a cloudy smudge in a telescope. Scientists have discovered several globular star clusters in M110’s halo, but those are much too small to be seen in an amateur telescope. For optimum viewing, don’t try to find M110 when the moon is bright, or in excessive light pollution. See if you can see its brighter center and its surrounding structure in your eyepiece.
M31 is a great target for skywatchers of any level, from those using their naked eyes to those using telescopes. If you wish to hunt for galaxies, I would recommend finding M31 first, as it is very easy to find and is bright. Telescope users will be treated to a 3 for 1 deal, as the satellite galaxies are easy to find as well. Looking at the Milky Way’s largest next door neighbor will be a memorable experience, even with the naked eye. Next time your outside on a clear dark night, have a look and see if you can find the Andromeda Galaxy, one of the most distant objects in the night sky you can see with just your eyes!
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