We’ve been dogged by clouds, so no Comet L4 PANSTARRS update from my backyard. Others across the U.S. have had better luck, spotting it just a few degrees above the western horizon a half hour after sunset. Despite its current magnitude of around 0 (bright as Vega in the Summer Triangle) the thick, hazy air near the horizon combined with the bright twilight glow have made it difficult to see with the naked eye. That should change in the coming nights as the comet inches upward into a darker sky.
Most observers say PANSTARRS is easy to see in binoculars with a very pretty tail. While you’re out hunting, don’t be fooled by airplane contrails. Sherrie of Ohio shared a photo of a very comet-like object with a bright head and short tail she saw low in the western sky on Friday night the 9th. After looking at several of her photos it became clear she had seen a “tail” of water vapor from a distant jet. In one of the photos, the sun briefly reflected off the plane creating a bright comet “head”. Very convincing.
You can tell the difference between a distant contrail and the comet after a few minutes. The contrail will change in length, brightness and overall appearance (or even disappear altogether) while PANSTARRS will look the same from the time you first spot it until setting. That goes for the angle of the tail, too. The comet’s tail is tipped up about 30-40 degrees to the upper right of horizontal. Contrails can appear at a variety of angles.
Video of Comet PANSTARRS setting over the Sierra Nevada Mts. from Sparks, Nevada by Jay Lawson
Today March 10, PANSTARRS reaches perihelion, when it will be closest to the sun at a distance of 28 million miles. This is when the comet feels the sun’s heat most intensely and waxes brightest. Dust-imbedded ices vaporized by sunlight create the comet’s fuzzy head and long tail. Once it leaves the sun’s vicinity, PANSTARRS will slowly fade but appear farther from the sun in a darker sky. With an orbital period of approximately 106,000 years, this will be the first and last chance any of us will behold this messenger from deep space.