Moon in Libra

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A pair of claws enfolds the gibbous Moon tonight -- the claws of Scorpius. As twilight fades, look for the scorpion's body curving away to the east of the Moon. Its brightest star, orange Antares, is to the Moon's lower left.

Technically, the Moon is in the middle of the constellation that's next door to Scorpius -- Libra, the balance scales. But in the earliest depictions, the scorpion had long claws that incorporated much of present-day Libra.

In fact, the proper names of Libra's brightest stars refer not to the scales, but to the scorpion. The stars are Zubenelgenubi and Zubeneschamali -- Arabic names that mean the southern and northern claws. The southern claw stands to the upper right of the Moon in early evening, and the northern claw directly above it.

It's not clear just how and when the scorpion lost its claws. Libra was first drawn thousands of years ago. Its name probably refers to a time when the Sun passed through that part of the sky at the autumnal equinox -- a time when day and night are equal, so the heavens appear balanced. But it's been several thousand years since the equinox moved out of Libra, so the constellation must be at least that old.

Even so, skywatchers from the days of ancient Greece to the Renaissance often referred to that region of the sky as the scorpion's claws, so it retained a sort of dual identity. And thanks to the names of Libra's bright stars, it keeps that identity even today.

Script by Damond Benningfield, Copyright 2004, 2008

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