By Peter Becker
Spring bird watchers don't have to wait till dawn to look for feathered friends. There's one in the night sky every spring evening. It's Corvus the Crow.
Crows may not be very colorful birds, but this is the dark of night. In mid-May, in mid- evening, the Crow constellation is visible "flying" due south, low in the sky. The principal stars hardly resemble a crow, but they make a neat trapezoid.
You can find Corvus to the right of the bright white star Spica. The star make a large "L" shape this season with the bright planet Saturn further left, and the bright yellow-orange star Arcturus, higher up at left (high in the southeast during May evenings).
The four principal stars of Corvus form the trapezoid shape; together they are sometimes called "Spica's Spanker" or the "Sail."
One of the constellation's stars has an interesting tale. 31 Crateris, which is magnitude 5.2 and dimly visible to the unaided eyes on a dark night, was once mistaken as a moon of Mercury! On March 27, 1974, two days before NASA's Mariner 10 was to flyby Mercury, instruments aboard detected ultraviolet radiation from what at first was interpreted by some astronomers as a satellite of the planet. It was later confirmed to be coming from a star in Corvus the Crow, which happened to be aligned near the planet as seen from the passing space probe.
Telescope users find among the deep cosmic treasures of the crow's nest, a few gems. The Antennae peculiar galaxy, NGC 4038 and 4039, includes two interacting galaxies that resemble a heart shape.
The Greek constellation Corvus was modeled after a raven in Babylonian mythology.
The best way to familiarize yourself with the constellations, if you don't have someone to point them out, is to get a star map for the time of year and time of night you are looking. Then you will be able to point the stars out to others. It doesn't take long to learn the names of the bright stars and star groupings.
Constellation charts may be found in astronomy field books normally found in public libraries; monthly magazines like Astronomy & Sky & Telescope and on many web sites.
Hold your chart so the direction you are facing is at bottom; most charts show the whole sky overhead; if you hold "south" at the bottom, then the eastern horizon stars are shown at left and western stars at right. To see the northern sky, turn yourself, and the map, completely around.
Your notes may be sent to firstname.lastname@example.org.
First quarter Moon is on May 18.
Keep looking up!