As I wrote in my Gettysburg Times column for February, this spring’s Comet PanSTARRS (C/2011 L4) is shaping up to be a bit of a letdown. Once forecast to reach easy naked eye visibility in early to mid-March, it now appears that it will require binoculars to pick it out of the glow of dusk. For full details, including diagrams, look at this Sky and Telescope article.
|View from Gettysburg on March 14, 30 min after sunset.
If Gettysburg had a very , very flat horizon.
Click to enlarge.
Here are my thoughts on local visibility. First, it’s key to find a flat western horizon away from artificial lights (no trees, hills, buildings). Very clear skies are a must. Any haze around the horizon will make sighting the comet much more difficult. Binoculars (preferably with at least 40mm aperture) will be the tool of choice. Get to your location about 20 minutes after sunset and begin scanning the sky around due west. The comet will be only about the width of a hand held at arm’s length above the horizon, and of course getting lower as the minutes go by. I would begin looking around March 9 and persist until I’d seen the comet! It will be higher above the horizon at sunset and farther to the north as the days go by, but fainter. We at the Hatter Planetarium would love to hear any local observing reports or photos. Send ’em to firstname.lastname@example.org.
Note: we are not planning any kind of public event at the Gettysburg College Observatory. The hill to the west of the observatory makes it a poor location for seeing PanSTARRS.