The Sky This Week, October 3-9
“The Sky This Week” appears every Tuesday. 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. Fall schedule of public shows is available here! Illustration created with Stellarium.
Let’s gaze into the deep southern sky this week. If you look to the east-southeast after dark, you’ll see bright and yellowish Saturn. About 20 degrees below Saturn is Folmalhaut, the southernmost first-magnitude star visible from our latitude. It’s the 18th brightest star in the sky, but since we never see it except in the glow of the southern horizon, that may be a little hard to believe. Fomalhaut is a member of the constellation Piscis Austrinus (the southern fish), though the rest of this constellation is hard to see from our latitude. Fomalhaut is about 25 light years away from Earth, and astronomers have detected a disk of debris surrounding the star, much as the sun had when our own solar system was forming.
About 30 degrees left of Fomalhaut is Diphda, a star in the constellation Cetus. Early Arabs are reported to have called the two stars First Frog and Second Frog, as they appear to leap across the southern horizon during the autumn months.
Watch for this column next week, as I will discuss the annular (partial locally) solar eclipse of October 14.
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.