Find the Andromeda Galaxy

The Andromeda Galaxy, also known as M31 or "the Great Spiral Galaxy",[1], is one of the most distant objects that the unaided human eye can see. It lies between 2.2 and 3 million light years away.[2] Locating it the first time is a little tricky, but once you find it, it's hard to ever lose it again.

Note: The best time for finding the Andromeda galaxy is between August and late March, so if you're experiencing difficulties locating it, bookmark this page and try again later. Also, be aware that this is easier to find in the northern hemisphere than in the southern hemisphere.

Steps

  1. Use binoculars for your first attempt at finding the Andromeda Galaxy. While you don't need to use anything other than your eyes, using binoculars will make it significantly easier for you as a beginner, and binoculars will give you a wider viewing zone than a telescope, which is important for a beginner. Also, choose a cloud-free night, and if you live where the stars are never seen, you'll need to go somewhere else.
  2. Locate three Make Up Your Own Star Constellation to get your bearings. You need to look for Find Astronomical Bodies, Cassiopeia and Andromeda. Pegasus was the flying horse in Greek mythology, and the end star of Andromeda goes into making the Square of Pegasus; it's easy to find because it's one of the largest geometrical shapes in the night sky.[1] Cassiopeia has a W or M shape which is easy to see and two of its end stars can be used as pointers to the constellation Andromeda.[1] Andromeda was a princess who was rescued from a monster by Perseus in Greek mythology.[1] The chart featured here shows the night sky for 35°N and is set for the 1st of December at 8:00 pm local, but can be used for later in the evening before that date and earlier after.
  3. Look for the distinguishing features. Pegasus is one of the easier to locate of the three, as it looks like a giant rectangle; this is the Great Square of Pegasus. Cassiopeia is even easier to locate, looking like a giant "M" or "W". Andromeda lies between them.
  4. Draw a line from the star Sirrah (also known as Alpheratz) on the edge of Pegasus and Andromeda to the star Ruchbah in Cassiopeia.
  5. Draw a line from Mirach through mu Andromedae and on through the first line. Keep in mind that mu Andromedae is dimmer than Mirach.
  6. Scan the area just to the southeast of where the lines meet, along the second line, with binoculars (or a small telescope - see next step). You'll notice an oval of faint light. This is the Andromeda Galaxy.
  7. Use a telescope for a more detailed examination. A typical 20cm (8 inch) reflector telescope will enable you to see 1,000 times further than the Andromeda Galaxy,[3] so you should get a great view with a standard telescope. When using a telescope, and especially in light-polluted skies, also try finding Cassiopeia, then using the "M" of Cassiopeia to point toward Mirach. After positioning Mirach in the telescope, move toward Locate the Double Cluster in Perseus to find the dimmer star, then more in that direction until you come across two fainter stars and a fuzzy object that forms a triangle with these two stars. This is the galaxy.
    • If you look carefully in binoculars or a telescope, you may find two faint fuzzy spots beside it. One of them, M32, is smaller in size and closer to the actual galaxy core. The other, NGC 205, is more elusive, larger in size, and farther from the actual galaxy. Both are companion galaxies to Andromeda.
    • You will probably be able to find it if you use a GOTO or computerised telescope. If you use an equatorial and know how to use setting circles, the Galaxy is at RA 00h43m, DEC +41deg16' .
    • If you're already familiar with using a telescope, you will be aware that its narrower field of vision than binoculars can make the targeting more precise and consequently harder. Thus, if you are a novice in using telescopes, leave this step until you're more confident.



Tips

  • If you are able to observe in a dark area away from streetlights, you are more likely to be able to find this object.
  • The Andromeda Galaxy can be seen even in relatively bright skies, but it might be a little harder to locate some of the fainter stars, so you may need to scan a slightly larger area.
  • While instruments such as binoculars and telescopes are not needed to locate this galaxy, they do make your viewing experience a lot clearer.
  • What you actually see is the core of the galaxy, the outer arms are very faint. You might wish to try to photograph it to make it show up, but you will likely need a long exposure time, a camera adapter, and image stacking software such as Registax or ImagesPlus.
  • In the opposite direction from the three/four bright stars, you may find two bright stars, and another faint star that appears as a double, which form a triangle. If you draw a line from the faint star to the spot in-between the two brighter stars, and keep going, you may find the Triangulum Galaxy, another bright but highly elusive galaxy.
  • The Andromeda Galaxy is 200,000 light years across and contains about 400 billion stars.[4] It is called M31 because it is the 31st object on Messier's list of diffuse sky objects.[5]
  • Two other galaxies can be easily seen from Earth with the naked eye: the Large Magellanic Cloud and the Small Magellanic Cloud. M33 is visible from a dark site and a few keen-eyed observers have spotted M81.[6]
  • A constellation is a group of stars like a dot-to-dot puzzle. If you join the dots–stars, that is–and use lots of imagination, the picture would look like an object, animal, or person. For example, Orion is a group of stars that the Greeks thought looked like a giant hunter with a sword attached to his belt.[7]

Warnings

  • This may be difficult to do in the southern hemisphere.
  • Remember to dress for the weather, especially in the colder months.

Things You'll Need

  • Binoculars and/or telescope
  • Camera and star atlas/planisphere (optional)

Related Articles

Sources and Citations

  1. ↑ 1.0 1.1 1.2 1.3 Lisa Miles and Alastair Smith, The Usborne Book of Astronomy & Space, p. 66, (2009), ISBN 978-1-4095-0843-4
  2. ↑ Leslie Alan Horvitz, Night Sky Tracker, p. 70, (2006), ISBN 1-84566-079-X
  3. ↑ Leslie Alan Horvitz, Night Sky Tracker, p. 18, (2006), ISBN 1-84566-079-X
  4. ↑ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question15.html
  5. ↑ http://science.nasa.gov/science-news/science-at-nasa/2000/ast26jan_1/
  6. ↑ Lisa Miles and Alastair Smith, The Usborne Book of Astronomy & Space, p. 90, (2009), ISBN 978-1-4095-0843-4
  7. ↑ NASA, http://spaceplace.nasa.gov/en/kids/st6starfinder/st6starfinder.shtml

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