| M10 and M12 are a pair of globular clusters about 3 degrees apart and similar in size and brightness. They are both about magnitude 6.6, making them good targets for telescopes of all sizes. Medium to large scopes will show hundreds of individual stars in both clusters. The stars of M12 are less densely packed, making them easier to resolve all the way to the center of the cluster. |
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| Evening visibility: |
June-September |
| Best viewed with: |
telescope |
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Printable chart (pdf) |
View larger image |
Directions:
Start by finding the constellation Ophiuchus, the serpent bearer, a large oval shape that is west of Arcturus (part of the Spring Triangle), east of Altair (part of the Summer Triangle), and north of Antares. The oval is about 25 degrees from top to bottom, and its main stars are second and third magnitude, so they should be easy to see with the naked eye even with moderate light pollution.
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| Look for the line of four stars that form the south end of Ophiuchus, stretching from Sabik in the east to Yed Prior in the west. In between is second-magnitude ζ (zeta) Ophiuchi. Use ζ and Yed Prior to form a triangle extending toward the center of Ophiuchus, as shown below, and M10 is at the northern corner of this triangle. To help find it, note that M10 is just 1 degree to the west of 30 Ophiuchi (magnitude 4.8), which will be easy to see in binoculars or a finderscope. After viewing M10, look slightly more than 3 degrees northwest to find M12. |
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| Star charts created with Cartes du Ciel |
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