Volume XVII, Issue 29 # July 16 - July 22, 2009

Sky Watch

by J. Alex Knoll

Forty Years Ago

Happy birthday Apollo 11

July 16 marks the 40th anniversary of the launching of Apollo 11 from Cape Canaveral, now named the Kennedy Space Center. Four days later, on July 20, the lunar lander touched down, and Neil Armstrong and Buzz Aldrin became the first men to walk on the moon.

This week you’ll have to stay up late or wake early to watch our 227,167-mile-distant natural satellite, but with a couple planets and several stellar neighbors at week’s end, it should be worth it.

The waning moon rises well after midnight this week, thinning away to nothing Wednesday the 22nd. If you’re up a couple hours past midnight Friday, look for the rising crescent in the northeast with dull-red Mars less than five degrees below the moon’s lower tip. A dozen degrees behind the moon and rising an hour later is the brilliant light of Venus. The red eye of Taurus the bull, Aldebaran, joins Venus, Mars and the moon to form the loose outline of the letter L. Aldebaran is almost identical to Mars in brightness and size but, traveling 68 light years to reach our eyes, the light of this star is distorted by stellar dust and clouds as well as our own atmosphere, causing it to shimmer and twinkle, unlike planets, whose light shines steady.

Look five degrees ahead of the moon and Mars for the Pleiades star cluster, which to the unaided eye looks like a dull blur of light. With clear conditions, however, a small telescope or even binoculars will reveal upwards of a dozen distinct stars. The Pleiades is the collective name of the seven daughters of Atlas and Pleione, but the cluster contains more than 1,000 stars. In recent years, astronomers using the the Spitzer Space Telescope and the Gemini Observatory in Hawaii have observed a mass of settling stellar dust surrounding many of these young stars, likely the formation of planets.

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.