Volume XVII, Issue 21 # May 21 - May 27, 2009

Sky Watch
by J. Alex Knoll

The Dioscuri

Look for these sons of Zeus high in the west at sunset

Early risers Friday morning can bid adieu to the thin waning crescent moon low in the east in the hour before dawn. Venus blazes 20 degrees to the moon’s right, and Mars sits midway between the two. The two planets are only a few degrees apart, but finding Mars may be a challenge better suited for binoculars. Not only is Venus bigger than the red planet, it is almost four times closer to us and two times closer to the sun.

The moon disappears amid the sun’s glare Saturday and Sunday, and a new sliver of moon emerges low in the west at twilight Monday. Tuesday the waxing crescent shines in the west with sunset at 8:20. About 15 degrees above the moon shine the twin stars of Gemini, Castor and Pollux. Wednesday evening, that gap narrows as the moon lines up six degrees to the left of the brighter, orange-hued Pollux with blue-white Castor just a few degrees farther.

In mythology, Castor and Pollux were the dioscuri, the sons of Zeus, conceived when the king of gods and men visited Leda, queen of the Spartans, in the form of a swan. From the union, Leda bore two eggs: from one came the mortal Castor and Clytemnestra; from the second came the immortal Pollux and his mortal sister Helen, whose beauty launched a thousand ships in the Trojan War.

Castor became a master horseman and Pollux the greatest boxer. The twins were seldom apart. They traveled with Jason aboard the Argo in his quest for the golden fleece. When storms threatened to sink the ship, Pollux appealed to his uncle, Poseidon, to calm the seas. When Castor was killed, Pollux begged his father Zeus to share his own immortality with his fallen brother, and so the two remain side by side in the heavens to this day.

Illustration: © Copyright 1925 M.C. Escher/Cordon Art-Baarn-Holland; Graphics: © Copyright 2009 Pacific Publishers. Reprinted by permission from the Tidelog graphic almanac. Bound copies of the annual Tidelog for Chesapeake Bay are $14.95 ppd. from Pacific Publishers, Box 480, Bolinas, CA 94924. Phone 415-868-2909. Weather affects tides. This information is believed to be reliable but no guarantee of accuracy is made by Bay Weekly or Pacific Publishers. The actual layout of Tidelog differs from that used in Bay Weekly. Tidelog graphics are repositioned to reflect Bay Weekly’s distribution cycle.Tides are based on National Oceanic and Atmospheric Administration and are positioned to coincide with high and low tides of Tidelog.