Volume XVII, Issue 24 # June 18 - June 24, 2009

Sky Watch
by J. Alex Knoll

The Day of Short Shadows

Summer’s long days make for short nights

These are the longest days of the year, with the sky not darkening until well after 8:30 and leaving us with barely six hours of astronomically dark skies. When the sun does set, Saturn appears high in the south, while Jupiter this week rises just before midnight. But the week’s best attractions come before dawn.

This weekend’s solstice is reason enough to rise early and greet the sun, but early risers will enjoy more than the dawning day.

Set your alarm early Friday, and look to the east for the waning crescent moon, which rises before 3am. Close behind is ruddy Mars followed by brilliant Venus, which shines 150 times brighter than Mars. The planets are less than two degrees apart, with the moon five degrees to the north of Mars, all close enough for your fist at arm’s length to obscure them.

While these two planets remain within a couple degrees of one another over the coming week, the fading crescent moon rises more than a half-hour later each morning, amid the stars of the Pleiades Cluster early Saturday and huddled low against the horizon with Mercury early Sunday.

Saturday is the longest day of the year, with summer solstice at 1:46am Sunday morning. The higher the sun rises in the sky, the more distance it travels from one horizon to the other. On the day of summer solstice, the sun rises at its farthest point north in the eastern sky, arching steeply through the day until nearly overhead at noon, casting sharp, short shadows. There, at its apex, the sun appears to pause, then finally angles downward, setting at its most northern point in the west roughly 14 hours and 54 minutes later.

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.