How to find the Andromeda galaxy
From mid-northern latitudes, you can see M31 – also called the Andromeda galaxy – for at least part of every night, all year long. But most people see the galaxy first in autumn, when it’s high enough in the sky to be seen from nightfall till daybreak. In late September and early October, the Andromeda galaxy shines in your eastern sky at nightfall, swings high overhead around midnight (1 a.m. daylight saving time) and stands rather high in the west at the onset of morning dawn. Winter evenings are also good for viewing the Andromeda galaxy.
If you are far from city lights, and it’s a moonless night – and you’re looking on an autumn or winter evening – it’s possible you’ll simply notice the galaxy in your night sky. It’s looks like a hazy patch in the sky, as wide across as a full moon.
But if you look, and don’t see the galaxy – yet you know you’re looking at a time when it’s above the horizon – you can star-hop to find the galaxy. You’ll be hopping to the Andromeda galaxy from the Great Square of Pegasus. In autumn, the Great Square of Pegasus looks like a great big baseball diamond in the eastern sky. Envision the bottom star of the Square’s four stars as home plate, then draw an imaginary line from the “first base” star though the “third base” star to locate two streamers of stars flying away from the Great Square. These stars belong to the constellation Andromeda the Princess.
On each streamer, go two stars north (left) of the third base star, locating the stars Mirach and Mu Andromedae. Draw a line from Mirach through Mu Andromedae, going twice the Mirach/Mu Andromedae distance. You’ve just landed on the Andromeda galaxy, which looks like a smudge of light to the unaided eye. If you can’t see the Andromeda galaxy with the eye alone, by all means use binoculars.
At 2.3 million light-years, the Great Andromeda galaxy (Messier 31) rates as one of the most distant objects you can see with the unaided eye. It is also the closest and brightest spiral galaxy to our Milky Way galaxy.
History and Science
Although a number of minor galaxies lodge closer to our Milky Way galaxy, the Andromeda galaxy is the closest major galaxy. Excluding the Large and Small Magellanic Clouds (which we can’t see from our northern latitudes), the Andromeda galaxy is the brightest in all the heavens.
The Andromeda galaxy and our Milky Way galaxy reign as the two most massive and dominant galaxies within the Local Group of Galaxies – our local galaxy cluster of over 30 galaxies. Both the Milky Way and the Andromeda galaxies lay claim to about a dozen satellite galaxies.
At one time, the Great Andromeda galaxy was called the Great Andromeda nebula. Astronomers thought this patch of light was composed of glowing gases, or was perhaps a solar system in the process of formation. It wasn’t until the 20th century that astronomers were able to resolve the Andromeda spiral nebula into individual stars. This discovery lead to a controversy about whether the Andromeda spiral nebula and other spiral nebulae lie within or outside the Milky Way. In the 1920′s Edwin Hubble finally put the matter to rest, when he used Cepheid variable stars within the Andromeda galaxy to determine that it is indeed an island universe residing beyond the bounds of the Milky Way galaxy.
The Andromeda galaxy (M31) is at RA: 0h 42.7m; Dec: 41o 16′ north
I need to know. Could the Hubble telescope detect the approximate percentage of young stars in the Andromeda galaxy through infrared light? And how soon will the Webb telescope be deployed into Earth orbit? Since the Webb will be far superior to the Hubble it would be amazing to discover what the Webb can reveal when directed at the Andromeda galaxy.
Is there any chance you can show a picture of what Andromeda would look like with a beginners level telescope? I recently purchased the Celstron Firstscope and I’m having difficulty finding Andromeda. I have a general idea of where it is, but I would like to see exactly what I’m looking for.
Thanks!
Mike,
SkyJack offers good advice. Binoculars have to be the most underrated tool in stargazing. Binoculars take in a much greater area of sky than the telescope, making it much easier to locate your target. Even the practiced telescope user relies on binoculars at times as a larger-view finder scope. For some stellar treasures (like the Coathanger cluster, for example) binoculars work better than the telescope, because binoculars place the object in a single field of view.
Hi Mike, might I suggest using first a pair of binoculars to locate Andromeda, scanning the area described by this article. You will no doubt find it. It will look like a fuzzy patch, sort of like if you covered the bright core of the galaxy in the photo accompanying this article with your finger; much smaller, of course. Once you have seen it, then use your finderscope to center it for your main telescope. Under the right dark sky conditions you can see Andromeda with the naked eye as well, small and fuzzy though, like a smudge. Good luck and clear skies!
I just love all the information that you give us,and i would like to ask your advise about which is the best pair of binoculars I can buy, I have already two pairs (16×32) and (10×25) but I know there must be something better out there, I been watching Jupiter for almost two weeks now, and I don’t get tired of doing the same thing every night ( I do have a life too ;)) my other favorite planet is Saturn, I saw it at the Griffing Park Observatory it was BEAUTIFUL!
i have a 10×25 and from what i understand it is far from ideal 4 stargazing. much better would b a 10×50. also other things r important such as fully multicoated lenses and perhaps porro-prism design, with BAK-4 glass better, that’s what i’ll b looking 4 when i upgrade.
Thanks for the info. Got to learn to find Andromeda in the sky easily and this will help!
Brian Carey
Can’t wait until the clouds go away, it’s been weeks! First object is M31, then the 7 Sisters.
Thank you Kayseri!
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[...] learned to find the Andromeda galaxy by star-hopping from the Great Square to the two stars marked here — first Mirach, then Mu [...]
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[...] M31: Great galaxy in Andromeda | Clusters Nebulae Galaxies …The Andromeda Nebula is one of our nearest neighbor galaxies. It is similar to the Milky Way in many ways. M31 is located at a distance of about 1 Megaparsec. [...]