Two possible ‘Great Comets’ coming in 2013

Posted: October 14, 2012 by phaedrap1 in News
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Few sights in our sky are more impressive than that of a “Great Comet.” Often appearing as bright (or brighter) than the brightest stars, and with bright tails that may span a considerable distance across the nighttime sky, such objects can be truly spectacular and awe-inspiring.

It is easy to see how ancient peoples, who didn’t understand their physical nature, often considered them as being supernatural phenomena, usually signs of divine displeasure.

Comets are relatively common phenomena, with several usually being accessible to larger backyard telescopes at any given time. Perhaps once a year or so, on the average, a comet will come along that is bright enough to view with the unaided eye, if a sky-watcher is located at a dark site and knows where to look. A “Great Comet,” however, is fairly rare, with such objects appearing perhaps only once a decade on the average.

For those of us in the northern hemisphere, it’s been a while. Our most recent “Great Comets” were the pair that appeared in the mid-1990s — Hyakutake in 1996 and Hale-Bopp a year later. While there have been several comets that have reached naked-eye visibility since then, none of these could really be considered to have reached “Great Comet” status.

Our friends south of the equator, however, have been more fortunate. Comet McNaught put on a spectacular show in early 2007 after briefly being bright enough to be visible during broad daylight. Late last year, Comet Lovejoy put on another great


As fate would have it, neither of these two comets were visible from the northern hemisphere when they were anywhere near the best, which has been rather frustrating for those of us skywatchers who live north of the equator. That frustration may be coming to an end, however, as not one, but two, inbound comets have the potential to become “Great Comets” as seen from the northern hemisphere in 2013.

The first of these two comets was discovered in June 2011 by the Panoramic Survey Telescope And Rapid Response System project, a comprehensive survey program based at Mount Haleakala, Hawaii, that became operational a little over two years ago. While Comet PANSTARRS was a very dim and distant object at the time of its discovery, it has brightened steadily since then. For the past several months it has been detectable with larger backyard telescopes as it slowly tracks across the constellations of Scorpius and Libra.

Comet PANSTARRS will be visible only from the southern hemisphere for the first two months of 2013, but by the beginning of March it begins to swing northward. At around the middle of that month it becomes visible from the northern hemisphere, quite possibly as a very bright object low in the west during evening twilight.

At that time it is also near its closest approaches to the sun (28 million miles) and Earth (102 million miles). Over subsequent weeks it continues tracking northward and becomes more easily visible, although it should also fade as it moves away from the sun and Earth.

By the latter part of May it will be high in the northern sky near Polaris, although by that time it will probably no longer be detectable with the unaided eye.

Meanwhile, just within the past week has come the discovery of another comet that has the potential to become even brighter. It was discovered Sept. 21 by two amateur astronomers, Vitali Nevski of Belarus and Artyom Novichonok of Russia, using a telescope owned by the International Scientific Optical Network based in Russia. The comet, currently quite dim and distant, and located near the bright star Pollux in the constellation Gemini, has been given the name “ISON.”

Comet ISON will be closest to the sun, less than 750,000 miles above the sun’s “surface,” near the end of November 2013, and will be closest to Earth (40 million miles) a month later. Potentially, it could be bright enough to be visible in broad daylight around the time it is nearest the sun.

Since it is very well placed for viewing from the northern hemisphere during the weeks afterward, it could become one of the best and brightest comets of the past several centuries.

In early 2014 it, like its predecessor was a few months earlier, will be located in far northern skies near Polaris and may still be visible to the unaided eye at that time.

There is a distinct similarity between the orbit of Comet ISON and that of the Great Comet of 1680, a very brilliant object that was undoubtedly one of the brightest comets of the past millennium. While Comet ISON is not identical to that earlier comet, it is conceivable that the two are related. Perhaps they were once part of the same comet sometime during the distant past. We may be able to tell for sure one way or the other over the next few months as we gather more data about Comet ISON’s orbit.

Of course, comets are notoriously unpredictable when it comes to their brightnesses, and it is distinctly possible that Comet PANSTARRS and/or Comet ISON could “fizzle” and fade away as they approach the sun. But it is also distinctly possible that either, or both, of them could become “Great Comets” that will rank among the brightest comets that will appear during our lifetimes.

We will just have to wait and see.
Alan Hale is a professional astronomer who resides in Cloudcroft. He is involved in various space-related research and educational activities throughout New Mexico and elsewhere. His website is

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