SATURN'S RINGS SURGE IN BRIGHTNESS: This Friday night, May 22nd, Saturn will be "at opposition"--that is, opposite the sun in the skies of Earth. The ringed planet rises in the east at sunset and soars through the southern sky at midnight, a golden "star" in the constellation Scorpius. [sky map]
Whenever Saturn is at opposition, its rings surge in brightness. Why? Scroll down for the explanation. On the way, check out these photos taken by amateur astronomer Anthony Wesley on May 19th:
"This is an animation of two Saturn images about 10 minutes apart," says Wesley, who used a 16-inch telescope in Australia. It shows gaps in Saturn's rings, clouds in the planet's atmosphere, and a famous hex-shaped storm around Saturn's north pole.
Getting such Hubblesque results from a backyard telescope requires a combination of good seeing and long years of experience. Wesley is one of the world's top amateur astrophotographers and he routinely produces images like this. Observers with less experience can take good photos, too, especially in the nights ahead as Saturn's rings brighten.
The brightening of Saturn's rings is called the "opposition effect." Saturn's rings are made of frozen chunks ranging in size from dust to houses. Sunlight directly backscattered from those ice particles causes the ring system to shine even more than usual for a few days around opposition. The exact mechanism involves shadow-hiding and possibly coherent backscattering.
Sternkarte für 22.05.2015: