Jimmy Westlake: Snow Moon eclipse
February 10, 2008
The full moon that falls during the month of February each year is called the Snow Moon, and this year’s Snow Moon is something special, indeed. On Feb. 20, the Snow Moon will be totally eclipsed for all of North America.
A total eclipse of the moon occurs when the full moon passes through the Earth’s shadow cone as it orbits the Earth. Earth’s shadow is much larger than the lunar orb, so the entire moon can fit into the dark shadow of the Earth. Reddened solar rays that squeak through the Earth’s atmosphere and around the globe of the Earth bathe the totally eclipsed moon with a reddish-orange light. This same light, when cast on Earth’s snowy mountaintops, is called alpenglow.
As a special bonus, the totally eclipsed Snow Moon will be flanked on each side by a bright object. Just above the eclipsed moon, the star Regulus will twinkle. Regulus means “The King” and is so named because this star represents the heart of Leo, the celestial lion. Below the moon and slightly to the left is an even brighter object, but this one is not a star. It is the beautiful ringed planet, Saturn. On the night of the eclipse, Saturn is only four days from its closest point to Earth for 2008. Any telescope will show its legendary rings and maybe even a moon or two nearby.
This prime-time eclipse begins at 6:43 p.m. when the left edge of the Snow Moon begins to darken. During the next hour, the moon will slowly slip into the Earth’s shadow until, at 8:01 p.m., the total phase of the eclipse begins. It will take 50 minutes for the moon to cross through the Earth’s shadow, during which the sky will darken and the stars will shine brightly around the reddish ghost of a moon. Use binoculars to enhance the spectacular view. At 8:51 p.m., the left edge of the moon will once again peep out into the sunlight, and by 10:09 p.m., the eclipse will come to an end.
If you don’t get to see this beautiful eclipse of the Snow Moon on Feb. 20, you won’t have another chance to see a total lunar eclipse until Dec. 21, 2010. So, think clear, bundle up against the cold, and stand out under the February skies with a friend or two to watch one of nature’s most wonderful events.
Professor Jimmy Westlake teaches astronomy and physics at Colorado Mountain College’s Alpine Campus. He is an avid astronomer whose photographs and articles have been published on the Web sites of CNN.com, NASA’s “Astronomy Picture of the Day” Web site, Spaceweather.com, Space.com, Discover.com, MSNBC.com, NationalGeographic.com and in Sky & Telescope, Astronomy, Night Sky, Discover, and WeatherWise magazines. His “Celestial News” article appears weekly in the Steamboat Pilot & Today. His “Cosmic Moment” radio spots can be heard on local radio station KFMU.