The Sky This Week, October 24-30
“The Sky This Week” appears regularly. It is written by Ian Clarke, Director of the Hatter Planetarium at Gettysburg College. The planetarium offers regular educational presentations about the stars and the skies; there’s something for early elementary through adults. We are accepting field trip requests for the 23-24 academic year. The fall schedule of public shows is available here! Illustrations created with Stellarium.
As the full moon of October 28 approaches, it is a good time to pause and consider the moon’s monthly journey around the earth. Looking east each evening, you can see the moon moves each night about the width of a fist held at arm’s length. It takes 27.3 days for the moon to return to the same place relative to the background stars. At the same time, the moon’s phase is changing. One way to think about the full moon phase is that it occurs the moment the moon is directly opposite (180 degrees) the sun in the sky. That’s why the full moon rises around sunset and sets around sunrise. The full phase cycle of the moon, from one full moon to the next, is 29.5 days.
Here are a few notes on this full moon. In almanac tradition, the next full moon after the Harvest Moon is known as the Hunter’s Moon. It’s really close to Jupiter! There will be a partial eclipse of the moon visible from Europe. The main show will be over by the time the moon rises in the eastern US, though you may just be able to detect the slight shading of a penumbral eclipse as the moon rises on October 28.
Ian Clarke is the director of the Hatter Planetarium at Gettysburg College. In addition he has taught introductory astronomy labs and first-year writing there for over 30 years (not necessarily all at the same time). He was educated at Biglerville High School, the University of Virginia, and the University of Iowa. He lives in Gettysburg.