Autumn is here, and it's a wonderful time for stargazing. Find out what's up from Spaceweather PHONE.
DARK FILAMENT: A dark filament is snaking across the sun today: image. Filaments are clouds of hydrogen held above the sun's surface by magnetic force fields. This one is remarkably long--more than 250,000 miles from end to end. If you have a solar telescope, take a look.
HARVEST MOON: Tonight's full moon has a special name--the "Harvest Moon." It's the full moon closest to the autumnal equinox. Long ago, before electric lights, farmers relied on the Harvest Moon to light up their fields at night, allowing them to harvest autumn crops even after sunset.
When the Harvest Moon rises tonight, go outside and look around. You might see some strange things.
Photo credit: Andy Skinner of Mariposa, California.
Extra: This particular Harvest Moon is unusually big--almost 12% wider than some full Moons we've seen earlier this year. Why? Because the Moon is near perigee, the side of the Moon's lopsided orbit that comes closest to Earth.
LUNAR AUREOLE: "Last night, I was letting the dogs out and taking the trash to the curb, when I looked up and noticed a straw-colored ring around the Moon," says Erika Rix of Zanesville, Ohio. "I immediately dropped the trash and could hear a tin can rolling down the driveway as I ran back into the house for a camera." She took these pictures:
This is a lunar aureole, cousin to the better-known lunar corona. Both are caused by water droplets in clouds. When the droplets are a jumble of different sizes, they produce a straw-colored ring--an aureole. When the droplets are all of the same size they produce a rainbow-colored ring--a corona. Look for both tonight!