S E P T E M B E R The Sun at Its Active Best
Solar max is here! Eleven years or so, sunspot activity peaks and the sun's disk becomes pockmarked blotches in larger numbers than usual. This year is the predicted peak, though the date can't e pinpointed until after the fact. Yet while astronomers can predict the approximate time of the peak, estimating the strength is more difficult.
Astronomers think that sunspots are caused by a constriction in the solar magnetic field below the photosphere, the visible surface of the sun. This diverts the outflow of energy through a particular region and cools it. Although surface appears black against the solar surface, this is merely a relative effect -- the photosphere shines at around 5800 Kelvin and thus radiate far less light.
Tracking the progress of sunspots across the sun's face can make a nice observing project. You should find that a sunspot takes about 27 days to make one complete rotation around the equator. Because the sun is gaseous, however, it doesn't rotate as a solid body, and spots at higher latitudes take longer to make the same trip. Sunspots also can change shape and size.
Over a few days, a tiny dark pore can burst into large, complex sunspot group -- and its development is fascinating to watch. The safest way to view the sun is to project its image onto a white card or into a carefully built box attached to the eyepiece end of a telescope. This keeps your eye far from the intense light transmitted through any optical device. A magnifying glass directed at the sin can cause paper to smolder and catch fire. A telescope concentrates far more light and will do even more damage to your eye -- so be careful.
Calendar
Last Quarter - Sept. 5
New Moon - Sept. 13
First Quarter - Sept. 20
Full Moon - Sept. 27
EDT
Celestial Calendar 2000
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