With St. Patrick’s Day this week, green naturally comes to mind. When a comet starts “greening up,” it’s a sign that it’s getting closer and brighter. Only two weeks ago, before departing the evening sky, 8th-magnitude Comet 2P/Encke glowed pale emerald. This week, periodic comet 41P/Tuttle-Giacobini-Kresak begins the best part of its 2017 apparition, dashing across the circumpolar sky and brightening as it goes. Its timing couldn’t be better. It’s visible almost the entire night from anywhere in the northern hemisphere, so if you play your Moon-cards right, you can see 41P/T-G-K in dark skies part of every night now through about April 8th.
http://www.skyandtelescope.com/observing/comet-41pt-g-k-glows-green-for-st-paddys-day/
