Saturn as viewed by the Cassini orbiter / NASA
Saturn, its rings and the moon Titan / NASA
Such a fine weekend with two clear nights and tiny hints of spring. Last night I heard the welcome monotone call of a saw-whet owl between the growl of snowmobiles. Saturday, the day named after the agricultural god Saturn, was a special day for that planet. It reached opposition Saturday night when it rose at sunset. Opposition simply means that the planet is opposite the sun in the sky and closest to Earth. Close in astronomy is a relative term of course. In this case, that would be 770 million miles.
You may have seen Saturn in Leo last week when the moon parked to the right of it during the eclipse. If not, it’s easy to find in the constellation of Leo the lion. Face northeast and find the Big Dipper around 8 p.m. Take the two stars at the top of the Dipper Bowl and shoot a line through them to the right. Keep going until you arrive at a pair of bright stars. The lower, brighter one is Saturn, and the upper one is Regulus, Leo’s brightest star. To find the outline of the entire constellation, just refer the photos below from the eclipse.
Saturn is the most distant of the easy naked eye planets and its cloudy atmosphere gives it a pale yellow tint. If you have a pair of 10x binoculars and can hold them very steady and focus sharply, you’ll see that the planet has an oblong shape caused by its rings. To truly appreciate their beauty however, you’ll need a small telescope. Nothing fancy mind you. Just something that magnifies at least 30x. The rings, which consist of chunks of ice and rock, are 150,000 miles across but only about 150 feet thick. Their tip varies as seen from Earth as Saturn orbits the sun. Every 15 years we see them edge-on, and in all but the very largest telescopes, they completely disappear. I’ve seen this weird aspect of the planet several times in my life and can tell you, that without its rings, Saturn is a stranger in the night sky. Watch for it to happen in 2009.
For many more photos of the Lord of the Rings, check out http://saturn.jpl.nasa.gov/home/index.cfm