Finding M45

M45: The Pleiades

The Pleiades; The Seven Sisters; Subaru
Open Cluster
Season Visible in Evening
Autumn & Winter; Oct – Feb
Conversation Notes
Nearby open cluster, clearly visible with naked eye. So close and large that it requires very low magnification – better in binoculars than in the telescope.

M45 is clearly visible in the winter sky – you don’t need instructions on finding it, just confirmation that that object is the one we are discussing. (It’s rather common to encounter people who have seen this object but think it is The Little Dipper. It does have a tiny dipper-like shape of stars, so this misunderstanding is understandable.)

In the Japanese language, this object is called “Subaru”, which is why a cluster of six stars is the logo on the grill of Subaru automobiles.

Open clusters are easy to find and observe in small telescopes, pretty, and scientifically important. This is a group of stars all born from a common cloud of gas and dust. Since they came from the same gas cloud they are, astronomically speaking, all about the same age and all about the same distance from us, and they all started with about the same chemical composition. Knowing that they are the same age and at the same distance, the fact that they have different appearances allows us to learn a great deal about stellar evolution – the different appearances can only be a result of the different masses of the different stars.

Finding M45

Look to the southern winter sky, approximately 45 degrees up from the horizon.
Find the constellation Orion, easy to locate by the distinctive “belt” of 3 close-spaced stars.
Move upward and to the right of Orion, at a distance of a little more than his height, looking for a compact, bright, roughly triangular knot of stars. That is M45.
In binoculars or a magnifying Finder, the cluster is very pretty.

In your telescope, you may find it actually looks worse than in the finder, because the cluster is so large that your telescope will not fit it all in the field of view.

Short-focal length telescopes such as small refractors, with wide-field eyepieces, can still show the entire cluster in its beauty.

All the above images were generated with Starry Night Pro.

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