UPDATED 6:20 p.m. Dec. 20
By BRUCE McCLURE
With weather forecasters predicting cloudy skies, St. Lawrence County residents probably will not be able to watch a total eclipse of the Moon in the wee hours after midnight and before dawn tonight.
The Full Moon will occur tonight, not the night of Dec. 21-22. Unfortunately, the National Weather Service is forecasting a slight chance of snow showers and mostly cloudy skies overnight.
A total lunar eclipse can only happen at Full Moon, or when the Moon sits opposite the Sun in Earth's sky. It's only at Full Moon that the Moon can pass directly through the Earth's dark cone-shaped shadow. Most of the time, however, the Full Moon eludes the Earth's shadow by swinging to the north or south of it.
If skies were to clear in the North Country the totally eclipsed Moon would look rather dark or it could appear coppery in color. The reddish glow on the totally eclipsed Moon comes from the atmospheric scattering of sunlight from all of the Earth's sunrises and sunsets.
Eclipse times on Tuesday, Dec. 21:
• Partial eclipse begins: 1:33 a.m.
• Total eclipse begins: 2:41 a.m.
• Greatest eclipse: 3:17 a.m.
• Total eclipse ends: 3:53 a.m.
• Partial eclipse ends: 5:01 a.m.
For more information on the Dec. 21 total lunar eclipse, read the EarthSky feature at http://earthsky.org/tonight/total-lunar-eclipse-for-the-americas-on-nigh....
-- Bruce McClure of Norwood is a freelance astronomer and a frequent contributor to "StarDate" and "Earth and Sky" radio programs. His web site is idialstars.com.
