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Use Cassiopeia to find Andromeda galaxy

Tonight, try star-hopping to the Andromeda galaxy from the constellation Cassiopeia the Queen. In a dark sky, you might even spot this hazy patch of light with no optical aid, as the ancient stargazers did before the days of light pollution.

But what if you can’t find the Andromeda galaxy with the eyes alone? Some stargazers use binoculars and star-hop to the Andromeda galaxy via this W-shaped constellation.

The image at right shows the view of the Andromeda galaxy through a telescope.

Cassiopeia appears low in the northeast sky at nightfall and early evening, then swings upward as evening deepens into late night. In the wee hours after midnight, Cassiopeia is found high over Polaris, the North Star. Note that one half of the W is more deeply notched than the other half. This deeper V is your “arrow” in the sky, pointing to the Andromeda galaxy.

Remember, on a dark night, this galaxy looks like a faint smudge of light. Once you’ve found it with the unaided eye or binoculars, try with a telescope – if you have one. The Andromeda galaxy is the nearest large spiral galaxy to our Milky Way. It’s about 2.5 million light-years away, teeming with hundreds of billions of stars.

Many people find the Andromeda galaxy from the two streams of stars extending from the Great Square (they are the constellation Andromeda). Or they find the galaxy via the constellation Cassiopeia. This photo via EarthSky Facebook friend Cattleya Flores Viray. Click here to expand image.

Draw an imaginary line from the star Kappa Cassiopeiae (abbreviated Kappa) through the star Schedar, then go about 3 times the Kappa-Schedar distance to locate the Andromeda galaxy (Messier 31). Click here for a larger chart

Bottom line: Some prefer the constellation Cassiopedia – which is easy to find, shaped like an M or W – as a jumping off point for locating the Andromeda galaxy.

More about M31: Great galaxy in Andromeda

Use the Great Square of Pegasus to find the Andromeda galaxy

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Bruce McClure