Yesterday, the comet 2011 L4 (called PANSTARRS after the Panoramic Survey Telescope and Rapid Response System) became visible in the Northern Hemisphere for the first time, meaning some of us north of the equator will have a chance to view a comet before ISON's passage in the fall. But you'll need the right conditions and the right approach to see this elusive comet.
Prior to this month, PANSTARRS, which was discovered in June 2011, has been visible only from the Southern Hemisphere. However, NASA points out that would-be comet viewers in the Northern Hemisphere will need to be in the right place at the right time to see it:
"There is a catch to viewing comet PANSTARRS," said [principal investigator of NASA's NEOWISE mission Amy] Mainzer. "This one is not that bright and is going to be low on the western horizon, so you'll need a relatively unobstructed view to the southwest at twilight and, of course, some good comet-watching weather."
Well, there is one more issue — the time of day, or night, to view it.
"Look too early and the sky will be too bright," said Rachel Stevenson, a NASA Postdoctoral Fellow at JPL. "Look too late, the comet will be too low and obstructed by the horizon. This comet has a relatively small window."
Over the next several days, PANSTARRS will be visible to those with an unobstructed view of the western horizon. The sun's glare may interfere with the view after the comet makes its closest approach to the sun on March 10th, but should be visible again by March 12th, after which it will gradually fade from view over the course of the month. Head over to NASA for more information on the comet, as well as photos of PANSTARRS taken from Western Australia.
Image Credit: NASA.