Update on April 5, 2013: If you live at mid-northern latitudes or farther north, you can still catch Comet PANSTARRS in binoculars. EarthSky’s sky blogger Bruce McClure, in northern New York, saw Comet PANSTARRS with binoculars in both the morning and evening sky on April 4. And again saw the comet in the April 5 morning sky. The comet is now near the Andromeda Galaxy and the two faint fuzzies are visible within the same binocular field. They appear together in the northwest after dark, and in the northeast before dawn.
The charts below – designed for April 2013 – show the comet’s location for April 3 and April 15. Comet PANSTARRS pairs with the Andromeda galaxy in early April and climbs upward toward the W-shaped constellation Cassiopeia during the first half of April. Use binoculars. Look to the northwest as soon as it gets dark, around 70 to 100 minutes after sunset. Better yet, perhaps, look for this comet in the northeast sky before dawn, around 100 to 70 minutes before sunrise. Comet PANSTARRS is intrinsically fainter now as it heads back out to the outer solar system, but it now appears against a darker sky background – especially in the morning sky – making it easier to spot. Plus the moon is waning in the morning sky. If you haven’t caught Comet PANSTARRS yet, try now!
By the way, there’s a second, brighter comet due to arrive on the scene later this year. Comet ISON might become a very bright comet, visible across the globe, by the end of 2013. But for now, PANSTARRS is still the comet of the hour.
A few tips on finding Comet PANSTARRS in the evening sky
Try star-hopping. You can draw an imaginary line from the star Aldebaran and past the Pleiades star cluster, going about four times the Aldebaran/Pleiades distance to get a ballpark idea of the comet’s location in the evening sky. Or you can star-hop using the constellation Cassiopeia in either the evening or morning sky, as shown on the above sky charts.
The brightest object in the Andromeda galaxy’s and comet’s part of the sky is the orange-colored star Mirach. (See the two sky charts above and zoomed-in evening chart below.) The Andromeda galaxy is about 8o to the right of the star Mirach in the evening sky. A fainter, white-colored star Mu Andromedae (abbreviated Mu on the sky chart) lies about midway between Mirach and the Andromeda galaxy. Remember, a typical binocular field of view spans about 5o of sky, so the stars Mirach and Mu Andromedae, or Mu Andromedae and the Andromeda galaxy should fit within the same binocular field of view. Once you see Mirach in your binoculars, go about one binocular field to the right to locate the Andromeda galaxy.
Look after dark but not too much after dark. The trick is to look when the sky is dark enough but when the comet is also high enough in the sky for optimal visibility. The best viewing window is probably from around 70 to 100 minutes after sunset, or 100 to 70 minutes before sunrise. Be sure to find a level and unobstructed horizon!
Look below for more about Comet PANSTARRS.
Comet PANSTARRS in early March 2013
March 5, 2013. Comet PANSTARRS passed closest to Earth at 1.10 Astronomical Units, (AU). One AU equals one Earth-sun distance, about 93 million miles or 150 million kilometers. In other words, at its closest, this comet was slightly farther from us than our distance from the sun. No worries about it hitting us.
Starting about March 7, 2013. PANSTARRS began appearing above the western horizon after sunset for viewers at U.S. latitudes. To see it, you will need an unobstructed, cloudless view of the west after sunset. It is best to pick a dark spot, away from streetlights. Look in the sunset direction, as soon as the sky darkens. The comet is just above the horizon.
March 10. This is when Comet PANSTARRS was expected to be brightest. Why? The comet passed closest to the sun – as close as our sun’s innermost planet, Mercury, about 28 million miles (45 million kilometers) away – on March 10. Comets are typically brightest and most active around the time they are closest to the sun when solar heating vaporizes ice and dust from the comet’s outer crust.
Comet PANSTARRS from mid- to late March 2013
Throughout March 2013. As seen from the Northern Hemisphere, the comet is low in the west after sunset. It will move northward each evening during March 2013 as it moves from being in front of the constellation Pisces to being in front of the constellations Pegasus and Andromeda. PANSTARRS does have a tail, but it’s primarily a binocular object. The comet will swing above the star Algenib on March 17/18, and above the star Alpheratz on March 25/26.
Comet PANSTARRS in April 2013
April 2013. No matter how bright it gets in March, the comet will surely fade as April arrives, as it moves away from the sun and back out into the depths of space. But it will be located far to the north on the sky’s dome and will be circumpolar for northerly latitudes in the Northern Hemisphere. That means it might be visible somewhere in the northern sky throughout the night for northern observers. What’s more, the comet will be near in the sky to another beautiful and fuzzy object in our night sky, the Andromeda Galaxy (M31), the nearest large spiral galaxy to our Milky Way. If the comet truly is bright then, and if it still has a substantial tail, it’ll be an awesome photo opportunity!
The PANSTARRS telescope in Hawaii discovered this comet in June 2011. Since comets carry the names of their discoverers, it has been designated C/2011 L4 (PANSTARRS). Only the largest telescopes on Earth could glimpse Comet PANSTARRS when it was first discovered, but amateurs telescopes began to pick it up by May 2012. By October 2012, its surrounding coma was seen to be large and fine at an estimated 75,000 miles (120,000 kilometers) wide.
By the way, Comet PANSTARRS is considered a non-periodic comet. It probably took millions of years to come from the great Oort comet cloud surrounding our solar system. Once it rounds the sun, experts say, its orbit will shorten to only 110,000 years. It is, for sure, a once-in-a-lifetime comet.
Bottom line: We know PANSTARRS has been a disappointment to some, although others got fabulous photos of it. In late March and early April, 2013, the comet is still visible – perhaps more visible than it was earlier this month – as seen in Northern Hemisphere skies. Comet PANSTARRS viewing guide, plus charts, in this post.
Deborah Byrd created the EarthSky radio series in 1991 and EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.