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VENUS & REGULUS: Prepare to wake up early: Just before sunrise on Sunday, Oct. 3rd, the planet Venus and the bright star Regulus will be beautifully close together in the eastern sky only 1/5 of one degree apart. You can see them with the unaided eye; indeed, you can't miss them. But try looking through binoculars, too. They'll both fit in the field of view--a lovely sight!--and you'll be able to see Regulus' blue color more vividly. [sky map]
AURORA WATCH: Solar activity is low--very low. But even when the sun is quiet, fitful geomagnetic storms can break out and spark auroras at high latitudes. Witness this picture taken on Sept. 29th by Peter Jeffery in the Northwest Territories of Canada. "The moon was almost full, but we still had a couple of great displays lasting about 15 to 20 minutes each," he says.
When solar activity does pick up again (it will happen) be alert for lights in the sky because northern autumn is aurora season.
BLUE MOON ALERT: Mount St. Helens in Washington is spewing ash and steam, and scientists say a bigger eruption could happen soon. This means sky watchers in western North America should be alert for blue moons in the weeks ahead.
A blue moon over Texas in 2003. [More]
That's right. Blue moons. Airborne particles from volcanoes can act like a color-filter, tinging the moon (or even the sun) blue. In recent years people have seen blue moons after the eruptions of El Chichon in 1983, Mount St. Helens in 1980 and Mount Pinatubo in 1991. The moon rises tonight at about 9 p.m..
STRANGE RAINBOW: "My son spotted this strange rainbow almost directly overhead at about 5:30 p.m. local time," reports John Meester of Oshawa, Canada. Not only was it upside-down, "there was no rain for hundreds of miles!" What's going on here? (continued below)
Atmospheric optics expert Les Cowley has the answer: "This is not a rainbow, but rather a type of ice crystal halo, a circumzenithal arc. It is made when sunlight passes through two faces of precisely aligned plate-shaped crystals. The resulting colors are marvellously separated and much purer than those of a rainbow. Look nearly overhead for circumzenithal arcs within an hour or two of sunrise or sunset."