¡Sky Caramba! Weekly astronomy blog for the week ending March 28, 2015
The total lunar eclipse of April 4, 2015 will be visible in its entirety from most of the Pacific Ocean and the islands in it, western Alaska, far northeast Russia, the eastern half of Australia and some other places.
From most of the Americas and the eastern part of the Pacific, the moon will set during the eclipse. So you might wake up to see the eclipse start but not get to see all of it. Watching an eclipsed moon setting is still a nice sight. For most of Asia, the Indian Ocean, and western Australia, this is a moonrise eclipse. And that’s cool too.
The entire eclipse, including the least visible parts, lasts about six hours. The most visible part is when the moon goes through the middle of Earth’s shadow. That part is three-and-a-half hours with a little less than five minutes of totality in the middle of it. This will be the shortest total lunar eclipse phase for any eclipse of the 21st Century.
The moon enters the penumbra at 09:01 Universal Time. That’s the outer part of Earth’s shadow. Earth is blocking only some of the sunlight heading to the moon, so you still see the moon pretty clearly.
An hour and 15 minutes later, the moon starts entering the central shadow or umbra where all of the sun’s light is blocked except for the little bit that goes through Earth’s atmosphere and is refracted to the moon. So the moon won’t go completely dark even during the less than five minutes of totality when it’s entirely in the central shadow from 11:58 to 12:03 UT.
The moon is entirely out of the central shadow at 13:45. Then you can try to watch whatever you can of the slight color changes as the moon emerges from the outer shadow which is complete at 14:59.
It’s perfectly safe to watch a lunar eclipse with the naked eye, binoculars, or a telescope. A magnified view helps you watch the shadow cross craters.