Moon and Regulus

StarDate: February 9, 2009

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There's a bit of a traffic jam around the lion this week. The Moon crosses through Leo's borders, while the planet Saturn loiters near the constellation's eastern edge. Leo rises by late evening, so the goings-on are visible through most of the night.

Things kick off with quite a nice display tonight, as the full Moon passes just a few degrees from Regulus, Leo's brightest star. Regulus is a little to the left or lower left of the Moon as they rise.

Regulus is actually a stellar family. The primary star -- the one that's visible to our eyes -- is a good bit hotter than the Sun, so it shines white, with perhaps the slightest hint of blue. It's also larger and more massive than the Sun.

In fact, it's one of the few stars whose size astronomers have actually measured. The stars are all incredibly far away. The distance to Regulus, for example, is more than 450 million million miles -- and as stars go, that's darned close. At that range, it takes a good-sized telescope to see a star as anything more than a pinpoint of light.

These days, though, astronomers are measuring the sizes of more stars by using new technology. They can combine the light of two or more telescopes, or use systems that compensate for the blurring effects of Earth's atmosphere. Both techniques produce incredibly sharp images of the sky -- allowing astronomers to "see" far more detail in the distant stars.

We'll talk about the Moon and Saturn tomorrow.

Script by Damond Benningfield, Copyright 2008

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