“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. Field trip requests are welcome. NOTE: field trip request form for 2022-23 is now live. The spring 2023 schedule of free shows is available here. Images created with Stellarium.
We will continue our break from our tour of bright winter stars to discuss Comet C/2022E3 (ZTF), which reaches its brightest as it passes closest to earth on February 5. Unfortunately, the headlines about this comet have been, at best, misleading. First, keep in mind this is basically a binocular comet. It would be difficult to glimpse with the unaided eye under the best of circumstances, but by unlucky coincidence, the moon will be full and in the sky all night just at the crucial time. A moonless window does open up after February 6, with the waning gibbous moon rising later and later after dark, but by then the comet will be fading. If you want to see this comet, definitely bring a good pair of binoculars. If you find a fuzzy spot in the right place, that’s it! The greenish color you have read about (due to diatomic carbon) will be best detected in a 6-8 inch or larger telescope. I have made a rough finder chart using Stellarium to accompany this article. For charts that are more detailed and an in-depth description of the comet and its appearance, see this Sky and Telescope article.
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.