M 10 and M 12 - Twin Globular Clusters

Photos by Pittendreigh


We lack good guide stars directing you to these twin globulars of M10 and M12. It may take some sweeping of the area with a pair of binoculars, but they are not very difficult to locate.

First, find the constellation Ophiuchus. Many beginners may not be acquainted with this constellation, but they probably be quite familiar with the teapot image of Sagittarius and the curving tail of Scorpius. Ophiuchus will be north of those readily recognizable constellations.

Use the head stars of Scorpius (Pi, Delta and Beta) to direct you to the area of M10 and M12. You should be able to see four stars in a row, irregularly spaced. These are Zeta, Upsilon, Epsilon and Delta. Continue beyond that to find the globular clusters.

Both M10 and M12 can be seen in the same binocular field of view.

Another way to locate the clusters is to find Epsilon Ophiuchi. Move your telescope ten degrees east of Epsilon, not quite all the way to the star 30 Ophiuchi. Then move northwest toward Lambda Ophiuchi to locate M12.

Whatever method you use, once you find one, the other globular will be easy.


Since the two clusters are so close, the observe should take time to sketch both and to compare the differences. M12 has the brighter core. Is there a difference is shape? Do you detect a graininess in one nebula better than the other?

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