Monday, September 20, 2010


CLOSE ENCOUNTER WITH JUPITER: Tonight, Earth and Jupiter converge for their closest encounter until 2022. The giant planet will soar overhead at midnight, outshining everything except the Moon itself. At this time, even a small telescope pointed at Jupiter will reveal the planet's moons, cloud belts and swirling storms. Take a look!
If Jupiter is up at midnight, it must be opposite the sun: diagram. Indeed, astronomers call this "Jupiter's night of opposition." The effect of opposition may be seen in the shadow of Jupiter's moon Io, shown here in a photo taken last night by Anthony Wesley of Australia:

"Io was almost on top of its own shadow," points out Wesley. "This is due to the near-perfect alignment of Jupiter, Earth and the sun."
In a coincidence of interplanetary proportions, Uranus is also at opposition tonight. This rare double opposition of two giant planets is a once-in-a-lifetime event. Unlike Jupiter, Uranus is barely visible to the naked eye, a result of its smaller size and greater distance. It looks great, however, through a small telescope. Just point your optics at Jupiter and you will find emerald Uranus about 1o away.

Tuesday, September 7, 2010