Comet PanSTARRS Keeps Getting Better

Since C/2012 K1's discovery two years ago, this first-time visitor from the outer solar system has brightened steadily and is now within reach of a small telescope and even binoculars.

Two-tailed Comet PanSTARRS

Comet PanSTARRS (C/2012 K1) fluoresces green and sports two extensions to its left — a short, bright dust tail and wispy gas tail — in this photo taken May 31, 2014.
Damian Peach

With the Moon departing the early evening sky this weekend, eager skywatchers have a delightful prize before their eyes: Comet PanSTARRS (C/2012 K1). This reliable visitor seems as if it's been around forever. Well, not quite but almost.

It was discovered more than two years ago by the Pan-STARRS 1 telescope atop the 10,000 foot summit of Haleakala volcano in Hawaii. At the time, the comet glowed a feeble 20th magnitude and was nearly as far as the planet Saturn.

Comet PanSTARRS's steady climb

Comet PanSTARRS (C/2012 K1) has brightened steadily since its discovery. The comet is expected to reach magnitude 6 or 7 magnitude in the fall, when it will be low in the morning sky for mid-northern latitude observers.
Seiichi Yoshida

That was then. C/2012 K1 has been fattening up on sunlight ever since. With its distance from the Sun shrinking from 8.7 astronomical units at discovery to 1.05 a.u. at its upcoming perihelion on August 27th, the comet has brightened to magnitude 8. This puts it within easy range of 50-mm binoculars from a dark-sky site.

I saw it a week ago with a simple pair of 8×40s as a blob of fuzzy light in the little constellation of Leo Minor. Through a 15-inch reflector at low magnification, C/2012 K1 displayed a bright, well-condensed coma swaddling a tiny, brighter nucleus. A lovely dust tail about ½° long extended to the east-northeast and seemed to flutter about according to the vagaries of averted vision. I could only detect a hint of the much fainter ion tail to the southeast.

Ready to have a look yourself? Face west at nightfall in the coming weeks and locate the familiar "backward question mark" asterism better known as the Sickle of Leo. The chart will help you star hop from there to the comet.

Comet PanSTARRS (C/2012 K1) spends mid-June in Leo Minor near the 4.5-magnitude star 21 Leo Minoris before gliding over the Sickle of Leo, highlighted by the 1st-magnitude star Regulus. Comet positions are shown for 10:30 p.m. EDT every five days from June 13th through August 2nd. Click to enlarge and print out for use at the telescope. Source: Chris Marriott's SkyMap

Comet PanSTARRS (C/2012 K1) spends mid-June in Leo Minor near the 4.5-magnitude star 21 Leo Minoris before gliding over the Sickle of Leo, highlighted by the 1st-magnitude star Regulus. Comet positions are shown for 10:30 p.m. EDT every five days from June 13th through August 2nd. Click to enlarge and print out for use at the telescope.
Source: Chris Marriott's SkyMap

While not a spectacular sight in binoculars, I encourage you to go for it. Binocular comets are few and far between, and this one is worth the risk of a few mosquito bites on a summer night. Besides, the next few weeks will be the last chance for mid-northern observers to catch C/2012 K1 at a convenient time and relatively high altitude.

Come mid-July, the comet dips into the twilight glow and disappears from view. It returns to view, this time in the morning sky before dawn, in mid-September, but it won't climb much higher than 20° for mid-northern skywatchers while swinging south from Hydra into Puppis.

In theory, Comet PanSTARRS should continue to brighten over this months-long interval. Will it crest to naked-eye brightness as the leaves start to fall? I've got my fingers crossed!


Bob King is the newest blogger here on SkyandTelescope.com. By day, he's a photographer and photo editor for Duluth News Tribune in Minnesota. At night, he morphs into veteran skygazer "Astro Bob." Check back for more of his musings about observing the night sky.

3 thoughts on “Comet PanSTARRS Keeps Getting Better

  1. Graham-Wolf

    C/2012 K1 (PanStarrs) continues to be monitored from the Barber Grove Observatory (BGO) at Lower Hutt, NZ. Recently, it passed close to 61 LMi and is steadily brightening. Easily visible in 10 x 50 WA Binoculars (7 deg FOV). My data is consistently similar to that of Chris Wyatt of Walcha, NSW who has a similar Research Grade GSO Dobsonian to mine. I frequently make use of “Stellarium” to pre-plan my observing runs and operate a Quad-Core Laptop

    C/2012 K1 is one of a dozen comets being simultaneously monitored as part of the Southern Hemisphere effort of T.A. directed by Guy HUrst of Basingstoke, UK. This groups of some 10-15 observers (world-wide) has been operating since the 1970s and provides valuable data to other research archives. So far, I’ve managed well over 10,000 measures of over 400 comets and some 500 apparitions over the last 50 or so years since Ikeya-Seki in October 1965.

    My latest telescope:- a near 1/20th wave version with HST Coatings is a 26cm f4.9. From my subhurban backyard at ~ 400x (GSO 2 inch ED Barlows, GSO Superviews and 2 inch 80 deg AFOV eyepieces), I can get as “deep” as Mv 14.5 near the Zenith. I usually use my 2 inch 2x ED GSO Research Grade Barlow to “sharpen up” the optical path. I home-brew my own Barlow Extension tubes, and even a 2 inch 52RKE! Compared to my (previous) home-built 18cm f5 Newtonian…. it’s an absolute weapon! Clear skies to all…

    Graham W. Wolf
    International Halley Watch (IHW) 1982-1988
    Ex Carter National Observatory of NZ (1980s, 1990s).
    2010 George Alcock Memorial Prize.

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