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Libra

(LEE-bra)

The Scales

Libra is the last of the zodiacal constellations to be recognized, and the only one that is named after an inanimate object:  a pair of balance scales.

Visibility: At 8:00 p.m. Standard Time (9:00 p.m. Daylight Saving) Libra is visible in early May rising low in the southeast. In June and July it moves through the summer ecliptic skies and is highest in the south in early July. By late August it is fading into the western horizon after sunset.

What to look for: Libra is located between Virgo to the west and Scorpius to the east along the Zodiac. Its two brightest stars are Zubenelgenubi (Alpha Librae), Arabic for "the Southern Claw," and Zubenelschamali (Beta Librae), "the Northern Claw." Gamma and Sigma Librae are slightly fainter stars that complete the skewed diamond that Libra describes in the night sky. 

Mythology: Libra represents the scales with which Astraeia, Goddess of Justice, weighs the deeds of the dead before consigning their spirits to reward in the Elysian Fields, or to punishment in Tartarus.

A deeper look: The Arabic names for Alpha and Beta Librae, Zubenelschemali and Zubenelgenubi, the Northern and Southern Claws, recall the ancient Greek name for this constellation, Chelae, the Claws. But a balance scale does not have claws. Where did these claws come from?

The answer is that Libra was once a part of the constellation Scorpius. This was originally seen as an even larger pattern than it is now, a pattern that included a huge pair of claws attached to the body of the Scorpion.

But it was observed that the fall Equinox - when the long days of summer were ending, the short days of winter lay ahead, and night and day were of equal length - fell when the Sun was in Chelae. Night and day were "in balance," and Chelae, the Claws, became Libra, the Balance Scale, a name popularized by the Romans.