No enthusiastic skywatcher misses a total eclipse of the moon, and if weather permits tonight, neither should you.
The spectacle is often more beautiful and interesting than one would think. During the time that the moon is entering into and later emerging from out of the Earth's shadow, secondary phenomena may be overlooked. You can also watch the eclipse live on Space.com, courtesy of NASA, the Slooh community telescope and the Virtual Telescope Project.
Observers that know what to look for have a better chance of seeing the stunning eclipse, weather permitting. This first total lunar eclipse of 2014 is set to begin tonight (April 14) into the wee hours of Tuesday morning (April 15). The lunar eclipse is set to begin at about 2 a.m. EDT (0600 GMT), and it should last about 3.5 hours. The eclipse should be visible, weather permitting, through most of North America and part of South America. [Total Lunar Eclipse of April 15: Visibility Maps (Gallery)]
Here is Space.com's full guide for what to expect during all stages of the eclipse:
Stage 1 @ 12:53 a.m. EDT: moon enters penumbra — The shadow cone of Earth has two parts: a dark, inner umbra, surrounding by a lighter penumbra. The penumbra is the pale outer portion of Earth's shadow. Although the eclipse begins officially at this moment, this is in essence an academic event. You won't see anything unusual happening to the moon — at least not just yet.
Earth's penumbral shadow is so faint that it remains invisible until the moon is deeply immersed in it. We must wait until the penumbra has reached roughly 70 percent across the moon’s disk. For about the next 45 minutes the full moon will continue to appear to shine normally although with each passing minute it is progressing ever deeper into Earth's outer shadow.
Stage 2 @ 1:39 a.m. EDT: Penumbral shadow begins to appear — Now the moon has progressed far enough into the penumbra so that the shadow should be evident on its disk. Start looking for a very subtle light shading to appear on the moon's left portion. This will become increasingly more and more evident as the minutes pass; the shading appearing to spread and deepen. Just before the moon begins to enter Earth's dark umbral shadow the penumbra should appear as an obvious smudge or tarnishing of the moon's left portion.
Stage 3 @ 1:58 a.m. EDT: Moon enters umbra — The moon now crosses into Earth's dark central shadow, called the umbra. A small dark scallop will begin to appear on the moon’s left-hand (eastern) limb. The partial phases of the eclipse begins, the pace quickens and the change is dramatic. The umbra is much darker than the penumbra and fairly sharp-edged.
As the minutes pass, the dark shadow appears to slowly creep across the moon's face. At first, the moon's limb may seem to vanish completely inside of the umbra, but much later, as it moves in deeper you'll probably notice it glowing dimly orange, red or brown. Notice also that the edge of Earth's shadow projected on the moon is curved. Here is visible evidence that the Earth is a sphere, as deduced by Aristotle from Iunar eclipses he observed in the 4th century BC. It's at this point that deep shadows of a brilliant moonlit night begin to fade away. ['Blood Moons' Explained: What Causes a Lunar Eclipse Tetrad? (Infographic)]