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EMERGING SUNSPOTS: More solar activity could be in the offing. As sunspot 1190 grows rapidly near the center of the solar disk, a new and large sunspot is rotating over the sun's eastern limb. A 24-hour movie from the Solar Dynamics Observatory shows how the sunspot number is increasing. Stay tuned.
APRIL AURORAS: The auroras this month have been something to shout about. Just ask this happy sky watcher, photographed by Ruslan Akhmetsafin in Siberia on April 13th:
The display came at the tail end of a geomagnetic storm sparked by solar wind hitting Earth's magnetic field on April 12th. The event was so strong, it sent Northern Lights spilling over the Canadian border into US states such as Michigan and Minnesota. The storm has since subsided, but another flare up is possible as the solar wind continues to blow. Aurora alerts: voice, text.
April 2011 Aurora Gallery
[previous Aprils: 2010, 2009, 2008, 2007, 2006, 2005, 2004, 2003, 2002]
SUN HALOES: As a member of the member of the Astronomy Section of the Rochester Academy of Science, Brian Oyer has developed a habit: "I'm always looking up at the sky," he says, "even during the day." On Tuesday morning, April 12th, he was really glad he did:
"When I stepped out of my house in Greece, New York, I saw a network of luminous rings and arcs surrounding the sun. It was such a large display, I had to combine two exposures to capture the whole thing."
These are ice haloes, caused by sunlight shining through ice crystals in high cirrus clouds. An expert analyzing Oyer's snapshot would count at least six distinct halo-types: the 22o halo, a pair of sundogs, an upper tangent arc, a suncave Parry arc, a supralateral arc, and a circumzenithal arc. Click here for labels.
Looking up: It's not a bad habit, after all.
more images: from Alex McCombie of Mexico, NY
April 2011 Aurora Gallery
[previous Aprils: 2010, 2009, 2008, 2007, 2006, 2005, 2004, 2003, 2002]