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METEORS FROM HALLEY'S COMET: NASA's network of all-sky cameras in the southeastern United States detected a surplus of fireballs on May 7th. Each one was a piece of Halley's Comet, source of the annual eta Aquarid meteor shower. The eta Aquarids were supposed to peak on May 6th as Earth passed through a stream of Halley-dust, but there seems to have been a delay. Worldwide counts from the International Meteor Organization agree that May 7th was better. Furthermore, the shower might not be finished yet, so stay tuned.
CHECK YOUR ODOMETER: "On the eve of International Astronomy Day, 2011, my 1998 Jeep Cherokee Sport passed a major milestone," reports astrophotographer Dennis Mammana of Borrego Springs, California. "Its odometer flipped over to 186,282 miles; in other words, it's taken 13 years and 8 months for my Jeep to travel the distance a beam of light can cover in just one second." (continued below)
"Over the years this vehicle has taken me to countless star parties and night sky photo shoots, and I expect it will continue to do so for many years," he adds. "Next stop... the Moon!"
Readers, check your odometer. How far have you gone? (Distances: Moon = 238,854 miles; geosynchronous orbit = 22,236 miles; L1 Lagrange point = 930,000 miles)
SUN HALOES: On May 6th, sky watchers in Belgium were stunned when they witnessed a heavenly apparition in broad daylight. "It was one of the brightest and most complex displays of sun haloes I have seen in 25 years of observing," reports Philippe Mollet, who took this picture:
image with labels | more images
"The phenomenon lasted for more than 30 minutes, long enough to phone and e-mail many friends and colleagues," he adds. "[It looks like] this was observed over a large part of our (little) country."
Sun haloes are caused by ice crystals in high clouds. "This wonderfully bright display proves that you do not need to be in polar regions to see them," notes atmospheric optics expert Les Cowley. "Temperatures in 3 to 6 mile high cirrus are more than cold enough to make the needed hexagonal prism shaped ice crystals. There are two sets of halos, those nearest the sun are made by rays that pass between crystal faces inclined at 60 degrees. The outer halos with widely separated colors are from faces inclined at 90 degrees. See the labeled image for halo names. The huge colourful halo is a supralateral arc. This halo is often very hard to distinguish from the much less common 46 degree circular halo but there are several clues to look for to tell them apart."
more images: from Hendrik Mertens of Londerzeel, Belgium; from Joel Bavais of Ath, Belgium; from Francesco De Comite of Mouscron (Belgium)
April 2011 Aurora Gallery
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