The Planetarium at UT Arlington, 700 Planetarium Place, will offer free telescopic observations of the Feb. 20 total lunar eclipse, beginning at 7 p.m., weather permitting.
Unlike a solar eclipse, an eclipse of the moon is always safe to look at. During a lunar eclipse, which can only happen when the moon is full, the moon passes into the Earth’s shadow in space. Lunar eclipses do not occur every full moon, however, because the moon’s orbit is tilted relative to the plane of the Earth’s orbit. Eclipses occur only when the sun, Earth, and moon line up, which can happen only a couple times per year.
Although sunlight does not directly hit the moon during a total lunar eclipse, some sunlight gets bent, or refracted, through Earth’s atmosphere.Planetarium Director Marc Rouleau said just as we see as red sunrises and sunsets, that red light gives the eclipsed moon a coppery appearance. Each eclipse is different, however, depending on the condition of the Earth’s atmosphere. Observers will be able to witness a total eclipse of the moon on Feb 20, provided there are no clouds that night.
There are two parts to every shadow, the lighter, outer penumbra, and an inner, darker umbra. A total eclipse occurs if the moon passes completely in the umbra. It is a partial eclipse if the moon goes partly through the umbra. If the moon goes through the penumbra only, it is a “penumbral eclipse.”
The greatest part of any eclipse is when the moon is completely within the umbra part of the Earth’s shadow, which will occur from 9:01 until 9:51 p.m. for the Feb. 20 event. This is the time the moon will be totally eclipsed. The moon will be partially eclipsed over a much longer period, however, from 7:43 p.m. to 11:09 p.m.
The timetable is as follows:
6:37 p.m. moon enters penumbra
7:43 p.m. moon enters umbra
9:01 p.m. moon completely within umbra
9:51 p.m. moon starts to exit umbra
11:09 p.m. moon leaves umbra completely
12:16 a.m. Feb. 21, moon leaves penumbra
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