LONG RANGE FORECAST: A hole in the sun's atmosphere will swing into geoeffective position during the last week of March. Solar wind flowing from the hole is expected to strike our planet's magnetic field and spark G1- to G2-class geomagnetic storms on March 28-29. Arctic sky watchers should be alert for auroras in the waxing springtime twilight. Free: Aurora Alerts
SPOTLESS SUN SPARKS AURORAS: The sun has been blank for 9 straight days. However, the absence of sunspots has had little effect on auroras around the Arctic Circle as the solar wind buffets Earth's magnetic field. Last night in Abisko, Sweden, Carson Reid witnessed an hours-long display of lights with ribbons of green dancing among the clouds:
"Right after I took this photo, the lights intensified and I completely stopped taking pictures," he says. "All I could do is stare. It was amazing."
Reid is a member of Earth to Sky Calculus. This week he's in Sweden with a team of 6 other students launching space weather balloons into the Arctic stratosphere. So far they've launched 3 balloons in only 5 days. One of the balloons went up at night to photograph auroras from 100,000 feet. Did it work? The payload is still being recovered from the Arctic tundra. Stay tuned for results.
VENUS IS A SKINNY CRESCENT: On March 25th, Venus will pass almost directly between Earth and the sun--an event astronomers call "inferior solar conjunction." As Venus approaches the sun, the planet is turning its night side toward us, reducing its luminous glow to a thin sliver. Shahrin Ahmad of Kuala Lumpur, Malaysia, photographed the crescent on March 15th:
"Venus is about 17º from sun, and shining at only 4.7% illumination," says Ahmad. "This is my clearest view so far. "
In the nights ahead, the crescent of Venus will become increasingly thin and circular. The horns of the crescent might actually touch when the Venus-sun angle is least on March 25th. This is the most beautiful time to observe Venus--but also the most perilous. The glare of the nearby sun magnified by a telescope can damage the eyes of anyone looking through the eyepiece.
Anthony J. Cook of the Griffith Observatory has some advice for observers: "I have observed Venus at conjunction, but only from within the shadow of a building, or by adding a mask to the front end of the telescope to fully shadow the optics from direct sunlight. This is tricky with a refractor or a catadioptric, because the optics start at the front end of the tube. Here at Griffith Observatory, I rotate the telescope dome to make sure the lens of the telescope is shaded from direct sunlight, even through it means that the lens will be partially blocked when aimed at Venus. With our Newtonian telescope, I add a curved cardboard mask at the front end of the tube to shadow the primary mirror."
For the rest of this week Venus can still be observed without elaborate precautions. Point your optics at the Evening Star in the western sky after sunset. Even ordinary binoculars will show the planet's lovely curve.
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