
In this image of Jupiter, the Moon, and Venus taken on February 26, 2012, Jupiter and the Moon are less than five degrees apart and the Moon and Venus (below) are about 12 degrees apart. Credit: Kelly Kizer Whitt
Often when I’m discussing what gorgeous sky events you should be on the lookout for, I describe them in terms of degrees. Perhaps Jupiter is just three degrees away from the Moon, or Saturn and Venus have a close encounter placing them only a half degree apart in the sky. But what, exactly, is a degree?
The sky is split up into 360 degrees. To get a general idea of how to measure degrees, amateur astronomers use their fist held at arm’s length. Extend your arm out from you, make a fist, and the distance from the top of your hand to the bottom is about 10 degrees. This works even though people have different size hands, because a child with a smaller hand will have a shorter arm length and therefore still block out about 10 degrees of sky with this trick. To check it for yourself, extend your arm and fist out toward the horizon. Then place your other arm and fist on top of the first and alternate them until you have counted to nine. You have just measured 90 degrees and your arm should now be straight up over your head, as it is 90 degrees from the horizon to the zenith. Read the rest of this post …






