By John Augustine
Night sky watchers are in for a treat in May as there will be a total lunar eclipse on the evening of May 15 extending past midnight.
Do you know what a lunar eclipse is? The sun shines on only half the earth at one time so a shadow is cast through space on the area behind the earth. If the moon passes into this shadow it is called a lunar eclipse. Why don’t we have a lunar eclipse every time the moon passes around the far side of the earth in its orbit? The reason is because the orbit of the moon is tilted and most of the time the moon passes either below the shadow or above the shadow. On occasion it passes into the shadow and —we have a lunar eclipse.
This only is able to happen on a night of a full moon. Do you know why? Draw a picture and see if you can figure out why.
One might think the moon would completely disappear when the moon enters this shadow of the earth but that is not the case. Light shining through the atmosphere of the earth is bent and dispersed somewhat so some light enters this shadow and lands on the moon giving it an orangish color. Depending on atmospheric condition on earth at the time the appearance of the moon can vary considerably from just barely visible dark orange to surprisingly bright orange.
The eclipse will start about 9:32 eastern daylight time as the moon enters the edge of the earth’s shadow, the penumbra. However you are unlikely to see much change until about an hour and a half later, 10:27, as the moon starts to enter the dark part of the shadow, the umbra. The moon will be totally eclipsed for about 1.5 hours from about 11:29 until 12:53. Then the moon starts to leave the shadow and will be totally out and brightly lit by about 2:50 am.
As the moon is totally eclipsed you will notice the stars and planets come out into brighter view. Even it it’s cloudy you will notice a definite darkening as the moon is eclipsed. Let’s hope for clear skies. Enjoy the spectacle!