Comet 41P/T-G-K Tangles With The Great Bear

Comet 41P/Tuttle-Giacobini-Kresak briefly paired up with the spiral galaxy NGC 3198 on evening of March 14. The comet was first discovered by American astronomer Horace Tuttle in 1858 and then rediscovered by two other astronomers, Michel Giacobini and Lubos Kresak, at later dates, the reason for its tongue-twisting name. Credit: Chris Schur

Comet 41P/Tuttle-Giacobini-Kresak should become bright enough this coming week to see in 10×50 binoculars as it hurries across Ursa Major the Great Bear. 41P returns to Earth’s vicinity every 5.4 years. Some years it plays out that the comet is particularly close to Earth. 2017 is one of them. On March 31-April 1, the comet will pass just 13.2 million miles away or 55 times the Earth-moon distance — its closest in more than a century.

As the comet passes closest to Earth (0.14 a.u.) from mid-March through early April, it zips across the circumpolar constellations Ursa Major and Draco. Viewing opportunities are excellent for observers in mid-northern latitudes where the comet’s up all night. The map shows stars to magnitude +7.5 with 41P/T-G-K’s position marked every 3 days at 9 p.m. Eastern Daylight Time. Click image for a full-size, printable chart. Map: Bob King, Source: Chris Marriott’s SkyMap

That’s great news for skywatchers, since it means that 41P/T-G-K could briefly become bright enough to see with the naked eye from a dark, rural sky around that time. Right now, it’s about magnitude +8 and appears as a faint, misty patch of light in binoculars. Photographs show that the comet has a very large coma nearly 1° across or twice the size of the full moon according to some estimates.

Get ready for a dandy gathering of the comet, Owl Nebula, and galaxy M108 on the night of March 21–22. This view shows the trio in a 1° field of view around 11 p.m. Central Daylight Time that evening.
Map: Bob King, Source: Stellarium

Best of all, at least if you live in the northern hemisphere, is that 41P is “circumpolar.” That means it’s in the northern sky and close enough to the polestar, Polaris, to never set. As the comet speeds across the bowl of the Big Dipper this week and into Draco the Dragon, it will remain visible all night and well placed for viewing in moonless skies through early April. You’ll have lots of chances to see it assuming that clouds don’t park themselves over your rooftop.

In a telescope, the comet will appear large, fuzzy and very diffuse with a brighter center. Using high magnifications of 200x and up, observers should watch for jets of material extending from the inner bright, “false” nucleus. The true nucleus, a solid body composed of dusty ice, is about 0.8 mile across (1.4 km) across and completely hidden by the dust that gets boiled off when sunlight vaporizes comet ices.

41P, while not bright like Comet Hale-Bopp or some other notables, takes center stage as the current brightest. Grab a pair of binoculars and watch its progress across the Dipper the next clear night.

6 Responses

  1. Ron Burk

    Great shot Bob. An inspiration. I have shared it as a new target with my astrophoto friends. Can you confirm the separation to M109 on 3/21-22? My charting software, CdC & C2A, show about 8 degrees. Regards, Ron

      1. Ron Burk

        Thanks Bob.
        A typo. I actually meant M108. But since my post I have gone back to CdC and after reloading the comet elements and upgrading to the latest version and changing the dates numerous times, phew!! CdC now matches your plot. Now I have to tackle C2A because that plot matches the first plot I got with CdC. I appreciate your help and work.

        1. astrobob

          You’re most welcome, Ron. Glad you have the right plot. You’re on your way now to the comet …

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