Sunday, July 6, 2008

Red, White, and Blue

Last night there was a nice line-up of Saturn, Mars, Regulus, and the Moon in the evening sky. Mars is red-orange and Regulus shines a bright bluish-white. Saturn is more whitish-yellow. Set against the evening azure sky, they made a beautiful sight in my binoculars.

The two planets and Regulus spanned about 5 degrees while the crescent Moon was another 5 degrees below Regulus. The colors are barely apparent in my photo. If you click on it to see the larger image, you will notice that the smaller objects are streaks. That is because I used an ordinary tripod to take the photo and not my telescope. That's how much the Earth rotates in just the 15 seconds it took to take the picture.

Regulus or Alpha Leonis is actually a triple star system in the constellation Leo the Lion. This means that its stars are gravitationally bound together, they don't just appear to be close together from our point of view. The name Regulus comes from "Rex" meaning "King." It was known as the "Kingly Star" or "The Lion's Heart" to the ancient Babylonians.

Over the next few nights, the Moon will edge towards a conjunction with Saturn which happens on July 10. This is the last month to see Saturn before it dips into the solar glare. It will be hidden from our view for about two months and re-appear in the morning sky in the fall. The rings are getting more and more edge-on, which means they will look like a straight line and be much harder to see. Everyone is so amazed when they see Saturn's rings for the first time. Usually the comment is, "It really does have rings!"

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