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ENCOUNTER WITH MARS: This weekend, Mars is closer to Earth than it will be again for another 13 years. Look for it rising in the east after sunset, brighter than any star in that part of the sky. Some people say Mars looks red, others say yellow or "pumpkin-colored." What do you think? [sky map]
DUST STORM: On Oct. 28th, a dust storm erupted on Mars. Amateur astronomer Joel Warren, using an 8-inch telescope, was one of the first to notice. He says "it was the most spectacular and intense cloud I've ever seen on Mars." It was certainly the strangest--the billowing cloud looked like an octopus:
Above: The dust storm photographed by Mark Schmidt of Racine, Wisconsin, on Oct. 28th and 29th.
The tentacles of the storm are spreading into the Sinus Meridiani region of Mars where NASA's rover Opportunity is located. In the days ahead, the rover might be able to photograph hazy skies or even experience blowing dust. Stay tuned.
Because of Mars' ongoing close encounter with Earth, details on the planet, such as this dust storm, are readily visible through backyard telescopes. "This is as good as it gets for observers of Mars," says Jim Melka of St. Louis, Missouri, who used a 12-inch telescope to snap this picture on Oct. 29th.
MONTANA MOONDOGS: Last week, John Thomas of Sun Prairie Village, Montana, was watching the night sky when a jet airplane cut across the moon. The moon lit up the contrail forming a pair of bright moondogs:
Above: The moon (center) flanked by moondogs (left and right). "The rainbow color of the rightmost moondog was visible in the photo, but not to the naked eye," notes photographer John Thomas.
Atmospheric optics expert Les Cowley comments: "Contrails are mini-clouds formed by the water vapour from aircraft engine exhausts. In the cold upper atmosphere the vapour cools rapidly to form very small ice crystals, too small to make halos. But this contrail was different. Unusually, the crystals here have grown into large plate shapes that have formed paraselenae or lunar sundogs. Always check out contrails, and smokestacks in cold weather, because they sometimes show us rare halos."
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