Total Lunar Eclipse!
A total eclipse of the moon will be visible on Saturday morning, December 10, 2011. A total lunar eclipse occurs when the sun, Earth, and Full Moon align, and the moon passes through Earth’s shadow.
The moon will first start to move into Earth’s shadow, called the umbra, at 4:46 a.m. PST. The moon will move deeper and deeper into Earth’s shadow until it is totally eclipsed, beginning at 6:06 a.m. Totality will continue until 6:57 a.m. at which time it will begin to leave the umbra. The subsequent partial eclipse will last until 8:18 a.m., but we will not be able to see the ending of the partial eclipse because the moon will set at about 7:20 a.m., which is also about the time of sunrise
The moon will be totally eclipsed for 51 minutes. The partial eclipse that occurs before totality will last for more than 1 1/4 hours, and we will also be able to see about 20 minutes of the partial eclipse that occurs after totality.
The totally eclipsed moon will take on a dull rusty red-orange color due to the absorption of the blue and green parts of the solar spectrum as sunlight passes through Earth’s atmosphere on its way toward the moon. In other words, the moon’s reddish glow is caused by light from all the sunrises and sunsets on Earth.
The moon at this time will be located in the western sky between the horns of Taurus the bull. The bright white star Capella will be above the moon. Red-orange planet Mars will be in the constellation Leo, which will be in the middle of the southern sky during the eclipse. The bright reddish star Arcturus will be in the east.
No telescopes or other optical aids are needed to see and enjoy the eclipse, but binoculars will make it more vivid.
The next total lunar eclipse visible from Napa will not occur until April, 2014, so don’t miss this one!
John Charlesworth (aka Star Man)
Professor of Physical Sciences, Emeritus (sort of)
Napa Valley College