The Sky This Week, September 5-11
“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! The fall schedule of public shows will be available very soon.
Milky Way from Hammersley Wild Area (PA), photo by Ian Clarke
Several weeks ago, I was asked via comment where the darkest skies are in the area. I’m happy to report that there is a website for this called darksitefinder.com, which offers a detailed map of light pollution. To help summarize the local and regional situation, I have taken a couple of screenshots from the map. First, the local situation: there are no truly dark skies in southcentral Pennsylvania, though the better skies in our area are plenty dark enough to see the Milky Way on a moonless summer night. The darkest local skies are north and west of Gettysburg, roughly aligning with Michaux State Forest north of US 30. Zooming out to the whole mid-Atlantic region will show you three inland areas of very dark skies. From north to south, these are aligned with the heart of the Adirondacks in New York, “The Wilds” of north central Pennsylvania, and an area of national forests around the Virginia-West Virginia border. The Pennsylvania dark sky region contains (but is not limited to!) our own designated dark sky park: Cherry Springs State Park. About four hours from Gettysburg, it offers an observing field and ranger-led activities. Even the darkest skies can be ruined by nearby light, so be sure to turn off any outdoor lights, put your phone away, and allow your eyes to adapt to the dark for at least 15 minutes.
At left, is a modified screenshot from darksitefinder.com, of the mid-Atlantic region; at right, a modified shot of the local area. Below, PA 44 near Cherry Springs State Park, photo by Ian Clarke
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.