Hold onto your shoes, friends, since Comet Lovejoy (C/2011 W3) is expected to put on such a spectacular light show (Dec. 14-15, 0211) as it approaches the Sun that it might blow your socks off. This comet is almost as wide as two football fields whereas most of the family of Kreutz comets are ten times smaller at only about 10 meters wide and could be the brightest comet that SOHO or STERO has ever seen. (Kreutz sungrazers are fragments of a single giant comet, probably the Great Comet of 1106, that broke apart back in the 12th century.) Comet Lovejoy (C/2011 W3) might become as bright as Jupiter or Venus when it is likely destroyed by the Sun: an eye-popping -3 Magntitude is one prediction.
You will not see this from Earth due to the brightness of the Sun, but several solar observatories (SDO, SOHO, Hinode, PROBA and STEREO) will have great views. "This comet is a true sungrazer, and will skim approximately 140,000 km (1.2 solar radii) above the solar surface on Dec. 15/16," notes Karl Battams of the Naval Research Lab. At such close range, solar heating will almost certainly destroy the icy interloper, creating a cloud of vapor and comet dust that will reflect lots of sunlight. Scientists are very excited about what we will be able to see and several special observation operations are planned.
The comet is currently visible in STEREO's HI1 instrument on both spacecraft, as seen in this video clip from STEREO-Behind from Dec. 12.
The Solar and Heliospheric Observatory (SOHO) will have a particularly good view of the comet's approach. The comet enters the field of view of the C3 coronagraph early on Dec. 14 from the lower left and will pass behind the Sun late Thursday night (Dec 15). You can follow its progress here: http://sohowww.nascom.nasa.gov/data/realtime/c3/512/
This is the basic trajectory that will be seen by SOHO and SDO:
STEREO will also be observing the comet from its positions on each side of the Sun. This is the view that the Ahead and Behind spacecraft will have:
Comet Lovejoy will reach STEREO's SECCHI COR-2 cameras, the SOHO/UVCS instrument, SOHO/LASCO C2 and SECCHI COR-1, and finally the EUV images on various spacecraft late Thursday night (Dec. 14) into Friday morning. You can follow developments on the Sungrazer web site.http://sungrazer.nrl.navy.mil/index.php?p=news/birthday_comet
Sit back and enjoy the show!