This coming spring (northern hemisphere) or autumn (southern hemisphere) we have a chance for viewing the first of two comets, Pan-STARRS (C/2011 L4), currently predicted to become naked-eye visible this year. Both comets could possibly reach 0 magnitude or brighter. The second comet, Comet ISON (C/2012 S1), is not expected to reach its predicted brightness until the end of this year, 2013.
Pan-STARRS (C/2011 L4) was discovered in June of 2011 and is named for its discoverer – an automated telescope, the Panoramic Survey Telescope & Rapid Response System. This telescope, equipped with a 1.4 billion pixel digital camera, was developed by the University of Hawaii’s Institute for Astronomy, and is operated by the PS1 Science Consortium .
An important comet caveat:
”Comets are like cats in that both have tails and both do what they want.”
Graphics used to depict the comet and its tail are from a computer program and are more accurate in showing the direction the tail points toward rather than the tail size.
Pan-STARRS (C/2011 L4) is a once-in-a-lifetime type of comet in that it has come into the inner solar system from perhaps as far away as the Oort Cloud and has an orbital period measured in probably tens of thousands of years or longer. However what makes this comet a potential bright comet is that it is closest to the Sun (10 March), and at its maximum activity of producing a tail, at about the same time as it is closest to the Earth (5 March). When closest to the Earth the comet will be about 1.09 AU away, which doesn’t sound too far, however 1.09 AU is 101,321,830 miles (163,061,679 km).The path that Pan-STARRS (C/2011 L4) is following has it approaching the Earth from the south and traveling north as it crosses the ecliptic plane – the Earth’s orbit. This means it will first become visible from the southern hemisphere before becoming visible in the evening sunset skies of the northern hemisphere.
This animated graphic shows the Path that Pan-STARRS (C/2011 L4) follows against the background of stars and constellations as the comet travels from the southern skies heading northward. The animation picks up during the comets’ approach as the comet reaches 6th magnitude in Telescopium. The animation ends when the comet again reaches 6th magnitude but now in Cassiopeia. Pan-STARRS (C/2011 L4)’s path starts in Telescopium, and then crosses the constellation boundaries of Microscopium, Grus, Pisces Austrinus, Sculptor, Aquarius, Cetus, Pisces, Andromeda, and Cassiopeia heading outbound from the inner solar system.Southern hemisphere observers will start seeing the comet around the beginning of February in the hours before sunrise and with the passage of days the comet will brighten and the tail will lengthen. Very interestingly due to the comet’s orbital path and position relative to the Sun the comet, after a week or so, will also be visible at sunset as this graphic set for 21 February shows. Depending on viewing location, latitude, and the weather the comet should remain visible into the first half of March from the southern hemisphere. From the mid-northern latitude (38 degrees) where I live the first view of the comet with a tail could be around March 5th at sunset local time. Gradually as it gets later in the evening and the sky darker the comet will become more visible but it will also be setting. However with each passing day the comet will be higher above the horizon so you could wait until it is darker a little later in the evening and the comet will be more visible with darker skies. The path the comet is following will take it toward the north and by early April the comet will be fainter with a smaller tail as it is moving away from us toward the outer solar system. Pan-STARRS (C/2011 L4) is predicted to reach its maximum brightness on 12 March, and on that date from the northern hemisphere mid-latitudes it will be above the western horizon with a very thin waxing crescent Moon and Mars at sunset local time as the above graphic shows. However one of the memorable viewings may be on April 3-4 when the comet passes a couple degrees from the Andromeda Galaxy, M-31.
Use this link to download a set of star charts made available by the Stephen F. Austin Observatory. This 6-page PDF format contains a 2-page equatorial star chart and two polar region star charts that could be used to track the comets position as the animated star path graphic above shows.
Remember that in the United States we go to Daylight Saving Time on March 10th so the times for sunrise and sunset shift by an hour. Combine this with the steady lengthening of daylight means that each day during March and April it will get darker a little later so if you wait until dark the comet will be lower. The short video below shows Comet PanSTAARS as hopefully it will be seen from 39oN at 7:15 p.m. CST and 8:15 p.m. CDT
“Impact Earth is a planetarium show that teaches about meteors, meteorites, asteroids, and comets. It includes results from recent NASA missions and about the dangers they can pose to life on Earth. It is created for fulldome theaters but is also available on DVD to be shown in flat version for TVs and computer monitors.”
This is one of many Discovery Dome Shows produced by Space Update Inc.
Click here to view this video online or learn about ordering it on a DVD.
Click here to go to the Qué tal in the Current Skies web site for more observing information.