सोमवार, २५ जुलै, २०११

Everyone’s favourite ringed planet is now visible in the night sky from sunset to sunrise. And it’s bright enough that you can’t miss it.
During stargazing sessions planned by many clubs across Canada this spring and summer—especially during Astronomy Week, May 2 to 8—Saturn will be the star attraction. It is always a crowd-pleaser. Every schoolchild has seen pictures of the ringed planet and drawn images of it in art class. In fact, in recent surveys, Saturn has consistently come in second after Pluto as the favourite planet. (That’s another story for later!) However, even adults gasp in amazement when they view Saturn through the eyepiece of a telescope. Pluto in a telescope is no competition whatsoever for the ringed gas giant.
I hear comments like: “It really does have rings!” or “That point of light beside it [Titan] is really bigger than our Moon?” or simply “Wow, that is AMAZING!” Seeing Saturn “live” is better than any photo in any book, even a Hubble Space Telescope image. (Maybe the Cassini spacecraft has an edge, since it is in orbit around Saturn.)
Once a year, Earth catches up with Saturn at a point called opposition, when Earth and Saturn line up so that Earth is between the Sun and Saturn. This puts the outer planet into our midnight sky, with the Sun on the opposite side of Earth. And since we are closest to Saturn then as well (a mere 1.3 billion kilometres this year), it is the brightest it can get in our sky. It appears to rise at sunset, move across the sky to its highest point above the horizon at midnight and then set in the west when the Sun is rising in the east. Now that the tilt of the rings has increased enough so that their curvature can be seen, Saturn is back again on the top of the list of showpiece objects to see through a telescope. Happy viewing!
John Hlynialuk is an amateur astronomer based in Owen Sound, Ontario.