This week, Comet PANSTARRS will be a naked eye object for observers in the northern hemisphere. But you need to be quick–it is low on the western horizon, close to the sun. If you are too early, the sky is too bright to see it. If you are too late, it will have already set. Fifteen to thirty minutes after sunset is the time to start looking. A pair of binoculars may help you spot it. Here is a helpful graphic from our friends at NASA, among the few government agencies people actually like.
It reaches its closest approach to the sun today (March 10), and moves farther away after that. If you look at the diagram, you can see that it also moves farther north each day. PANSTARRS has been visible in the southern hemisphere for some time now, but is only coming into view for those us north of the equator in recent days. This image may help explain why.
The comet is moving from bottom to top (south to north) in this view, which is along the plane of the solar system.
Finally, what’s up with that weird name? Comets are named for their discoverers, so we have perfectly understandable names like Comet West, Comet Hale-Bopp (joint discovery) or even Comet Shoemaker-Levy 9 (the ninth joint discovery by these folks). Increasingly, however, comets are being discovered by automated surveys dedicated to the task. Pan-Starrs stands for Panoramic Survey Telescope and Rapid Response System. Based in Hawaii, where about 75% of the entire sky is visible, its cameras can image all of that in about a week. These images can be compared to the previous ones, and any change will reveal a solar system object (close enough so that its motion is detectable) such as an asteroid or comet. It’s operated by the Air Force, and its main purpose is to detect possibly hazardous Near-Earth Objects. Every once in a while we get a nice bonus!