Get Set For Comet K1 PanSTARRS: A Guide to its Spring Appearance

Get those binoculars ready: an icy interloper from the Oort cloud is about to grace the night sky.

The comet is C/2012 K1 PanSTARRS, and it’s currently just passed from the constellation Hercules into Corona Borealis and presents a good target for observers high in the sky in the hours before dawn. In fact, from our Tampa based latitude, K1 PanSTARRS is nearly at the zenith at around 6 AM local.

Observers currently place K1 PanSTARRS at magnitude +10.5 and brightening and showing a small condensed coma. Through the eyepiece, a comet at this stage will often resemble a fuzzy, unresolved globular star cluster.

And the good news is, K1 PanSTARRS will continue to brighten, headed northward through the early morning and then into the evening sky before reaching solar conjunction on August 9th, when it’ll actually pass behind the Sun for a few hours as seen from from our vantage point. We actually get two good apparitions of Comet K1 PanSTARRS: one for the northern hemisphere in the Spring and one for the southern hemisphere after it reaches perihelion and crosses south of the ecliptic plane in August.

And it’ll be worth keeping an eye out for K1 PanSTARRS online as well, as it passes into the view of SOHO’s LASCO C3 camera on August 2 before exiting its 15 degree field of view on August 16th.

This actually means the comet will reach opposition twice from our Earthbound vantage point: once on April 15^th, and again on November 7^th. And, as is often the case, this comet arrives six months early –or late, depending how you look at it- to be a fine naked eye object. Had K1 PanSTARRS reached perihelion in January, we’d have really been in for a show, with the comet only around 0.05 Astronomical Units (about 7.7 million kilometers) from the Earth!

But alas, such was not to be. At its best, K1 PanSTARRS will be hidden by the glare of the Sun at its very best, to emerge into the southern sky. The comet has a steeply inclined 142 degree retrograde orbit, and thus approaches the inner solar system from high above the ecliptic plane.

These coming last weeks of March are a great time to search out K1 PanSTARRS as the Moon reaches Last Quarter this weekend and heads towards New on March 30^th, beginning a two week “moonless period for AM observing in early April. Projections by veteran comet observer Seiichi Yoshida suggest that K1 PanSTARRS will begin to brighten dramatically towards +8^th magnitude through April. We first picked up the now posthumous comet ISON with binoculars around this magnitude last Fall. Keep in mind, like nebula and galaxies, the apparent brightness of a comet is spread out over its surface area. This can make a +10^th magnitude comet much tougher to spot than a pinpoint +10 magnitude star.

We actually prefer our trusty Canon 15x45IS image stabilized binoculars for comet hunting… they’re powerful and easy to deploy on a cold March morning!

Here’s a handy list of notable events to watch for as Comet C/2012 K1 PanSTARRS crosses the springtime sky. Only passages of less than one degree near stars greater than magnitude +6 are mentioned except where otherwise noted:

March 17^th: Comet C/2012 K1 PanSTARRS passes into the constellation Corona Borealis.

March 21^st: Passes the +5.8 magnitude star Upsilon Coronae Borealis.

March 29^th: Passes the +5.4 magnitude star Rho Coronae Borealis.

March 30^th: The Moon reaches New phase.

April 2^nd: Passes the +4.8 magnitude star Kappa Coronae Borealis.

April 7^th: Passes the +5.2 magnitude star Mu Coronae Borealis.

April 10^th: Passes into the constellation of Boötes.

April 10^th: Passes the +5 magnitude wide binary pair Nu Boötis.

April 15^th: Comet K1 PanSTARRS reaches opposition, rising opposite to the setting Sun and moving into the evening sky.

April 20^th: K1 PanSTARRS becomes circumpolar for observers above 45 degrees north until May 25th.

April 26^th: Passes into the constellation Ursa Majoris.

April 29^th: Passes the bright +1.9^th magnitude star Alkaid in the handle of the Big Dipper asterism. This is the brightest star that K1 PanSTARRS will pass near for this apparition, and Alkaid will make a great “finder” to spot the comet.

April 29^th: The Moon reaches New phase.

April 30^th: Approaches the +4.7 magnitude star 24 Canum Venaticorum.

May 1^st: Passes into the constellation Canes Venatici.

May 1^st:  Passes less than 2 degrees from the galaxy M51… photo op!

May 3^rd: Passes the 5.1 magnitude star 21 Canum Venaticorum.

May 6^th: K1 PanSTARRS Reaches a maximum declination of 49.5 degrees north.

May 11^th: Passes the 5.3 magnitude star 3 Canum Venaticorum.

May 14^th: Passes into the constellation Ursa Major.

May 17^th: Another great photo ops awaits astrophotographers, as the comet passes the +3.7 magnitude star Chi Ursae Majoris and the +12 magnitude galaxy NGC 3877.

May 25^th: Passes the 3^rd magnitude star Psi Ursae Majoris.

May 28^th: The Moon reaches New phase.

May 28^th: Passes the 4.7 magnitude star Omega Ursae Majoris.

June 7^th Passes into the constellation Leo Minor.

June 15^th: Passes the +4.5 magnitude star 21 Leo Minoris.

June 22^nd: Passes into the constellation Leo.

July 1- Passes to within 40 degrees elongation from the Sun.

And from there, Comet K1 PanSTARRS reaches perihelion just outside of the Earth’s orbit at 1.05 A.U. on August 27, and plunges south across the celestial equator on September 15.

Video animation of comet C/2012 K1 PanSTARRS over the span of an evening. Credit: Dan Crowson of Dardenne Prairie Missouri, used with permission. 

It’s also worth noting that K1 PanSTARRS will make its first of two approaches at a minimum distance of 1.471 A.U.s from Earth May 4^th and will be moving at about a degree a day – twice the diameter of the Full Moon – before receding from us once more for a closer 1.056 A.U.  approach to Earth on August 25^th.

Discovered on May 19^th, 2012 by the PanSTARRS telescope based on the island of Maui, Comet K1 PanSTARRS was first spotted at 8.7 A.U.s distant, well past the orbit of Jupiter.  The PanSTARRS survey has been a prolific discoverer of asteroids and comets, including the brilliant comet C/2011 L4 PanSTARRS that graced dusk skies in March of last year.

Comet K1 PanSTARRS will join the ranks of comets reaching binocular observability later this year which includes C/2013 V5 Oukaimeden, Comet C/2013 A1 Siding Spring, and the recently discovered C/2014 E2 Jacques, which may reach +7^th magnitude as it nears perihelion this coming July.

And those are just the binocular comets that are scheduled to perform… remember, the next “big one” could come barreling in towards the inner solar system at any time to put on a memorable performance worthy of another comet Hyakutake or Hale-Bopp… just not TOO close!

–      Be sure to send those comet pics in to Universe Today.