Comet ISON Suddenly Brightens

Comet ISON Suddenly Brightens

As you may have heard by now, between November 12 and 14, Comet ISON suddenly brightened by two magnitudes (6.3 times brighter). Possibly a new crack or vent on the comet's surface opened up to allow the release of “fresh” material from below. Or perhaps the comet started rotating (some early research had suggested it wasn't). The onset of rotation could allow portions of the comet that had not yet been subjected to the Sun’s heating or solar wind to now react to either of those influences. Speculation has also arisen that ISON's nucleus may be fragmenting.

While astrophotographers have been imaging ISON for some time, only after this recent outburst of activity has the comet been seen with the naked-eye from dark sky locations. I tried to find ISON with a pair of 7x50 binoculars this morning (11/19) from about 4:55 until 5:15am, but to no avail. I could see Virgo's bright star Spica, plus some fainter stars below it, but ISON eluded my detection. I think this was due in part to the just past Full Moon bathing the sky in light, combined with a little low haze within 15 degrees of the southeastern horizon. There was also a cold wind at ground level, and Spica was sparkling like a diamond due to upper atmospheric turbulence.

My good friend and associate, Scott MacNeill, Associate Director of the Frosty Drew Observatory in Ninigret Park in Charlestown, had this to say about his November 15 search for ISON using binoculars: "...when I attempted a view with binoculars on the 15th I overlooked it for about 10 minutes as I thought it was a star in the field. Eventually I noticed the tail using averted vision and was surprised at how bright it was." (Frosty Drew Observatory has exceptional skies!)

GET THE LATEST BREAKING NEWS HERE -- SIGN UP FOR GOLOCAL FREE DAILY EBLAST

Scott was successful in obtaining a telescopic image of ISON that same morning using a Meade 8-inch Schmidt-Cassegrain Telescope. See image attached.

As the week progresses, ISON will move closer to the horizon and a rendezvous with the Sun on Thanksgiving Day. Also, the waning Moon will unfortunately be sliding to the east about 12 degrees each day. Though the moonlight will diminish as its phase decreases to last quarter to waning crescent, it will be moving in the general direction of the comet. Soon an observer will require a dead horizon to the southeast in order to catch a glimpse of ISON, with or without optical aid.

Time will tell if the brightening is a short-lived effect or not. It is possible ISON could still provide some outstanding naked-eye views during the next week. Whether it will survive its close encounter with the Sun is still a matter for speculation.