Set your alarm for anytime between 2:00am and 4:30am on Tuesday, April 15 so that you won’t miss an opportunity to watch a total lunar eclipse. This occurs when the moon passes through the very center or darkest portion of the earth’s shadow called the umbra. This happens when the sun, the earth and the moon are in a straight line with the earth in the middle. Most of the time at full moon the moon passes either above or below the earth’s shadow but not this time
So next Tuesday morning the moon will be passing through the earth’s shadow at 2,300mph and will remain in the dark shadow for about just over one hour. This will be between 3:06am and 4:24am in the western sky. During this time the only light able to reach the moon is sunlight that is being bent or refracted by the earth’s atmosphere into the earth’s shadow. This is the kind of reddish sunlight we see just before sunrise and just after sunset.
Due to the atmosphere bending and scattering sunlight the color appears more reddish and this is why during a total lunar eclipse the moon can appear rusty or deep red and hence the term ‘blood moon’. Here’s a sequence of images taken during a lunar eclipse to show this effect:
The color next Tuesday morning may not be as vivid or dramatic as this but it’s always interesting to see just how red the moon will appear. In my experience with watching a lunar eclipse I’ve seen the moon simply turn dark gray or brownish in color. However should there by a lot of dust in the atmosphere like from a volcano the red can be very pronounced.
Hopefully the weather will cooperate. However I see a chance that it may not. But even with a broken layer of clouds the effect can be every bit as dramatic as if the sky were clear. You don’t need a telescope to watch a lunar eclipse but watching through binoculars will greatly enhance the view. If you miss it… the next best time as good as this one will be in on September 27, 2015. That lunar eclipse one will start at around 9:00pm. No alarm clock required.