Three comets expected this year, two dim and one bright
Comet Pan-STARRS (C/2011 L4): visible March 5 until April 2013: this Comet will pass within one AU from the Earth as it proceeds onward to dip inside the orbit of Mercury. It is dim but visible with the unaided eye.
From Earth, the comet will appear close to the Sun, and it will only be observable briefly on the north-western horizon just after sunset, close to the crescent Moon on March 13. It’s only viewable for about 20 minutes, from about 8:15 until 8:40pm Mountain Daylight Time. The sky is too bright after sunset so you have to wait until about 8:15 when the sky darkens, but if there are mountains on the horizon, it will set below them within 15 or 20 minutes. It’s on the Northwest horizon, above Pegasus. It’s difficult to see at first, binoculars help a lot. It’s slowly moving North, by April 1 it will move closer to the Andromeda Galaxy.
Comet Pan-STARRS was discovered by the 1.8 meter telescope at the Panoramic Survey Telescope and Rapid Response System atop the Haleakala volcano in Hawaii, and named “Pan-STARRS” in it’s honour. It’s in a hyperbolic path, for orbital elements see JPL C/2011 L4
Comet Lemmon (C/2012 F6) already visible as a green blob in the Southern hemisphere, will be visible in the Northern hemisphere by April 2013 as it recedes back into the outer solar system on its 11,000-year orbit. Rather dim, it requires a telescope or binoculars to observe it. For orbital elements see JPL C/2012 F6
On November 2013: Comet ISON (C/2012 S1) could shine as brightly as a full Moon in broad daylight when it passes through the atmosphere of the sun. Although the comet is now only passing Jupiter’s orbit, more than 4.9 AU (763 million kilometers) from the sun, it already has a tail 64,400 km long. See JPL C/2012 S1
ISON was discovered on 21 Sept. 2012, by two Russian astronomers using the International Scientific Optical Network’s 16-inch telescope near Kislovodsk. And therefore named Comet ISON.
On 15 Feb 2013, Asteroid 2012 DA14, a 150-ft diameter stone skimmed by the Earth, passing inside the ring of geosynchronous satellites, 27,700 km above the Earth’s surface, before zipping back out into space at 7.8 km/s.