http://spaceweather.com/Discovered in 2013 by the Catalina Sky Survey, Comet Catalina (C/2013 US10) is making a one-time trip through the inner solar system. It swung around the sun last November and is now making its closest approach to Earth: 67 million miles away on Jan. 17-18. Yasushi Aoshima sends this picture from Shizuoka, Japan:
"I caught the comet just as it was passing Pinwheel Galaxy M101," says Aoshima. The full-sized image also shows the double star system Mizar and Alcor in the handle of the Big Dipper. Aoshima notes a discontinuity in the comet's gaseous ion tail, labeled here. "That is a drastic change since my last imaging session," says Aoshima. It is probably a sign that the tail is being buffeted and deformed by irregularities in the solar wind.
The 6th magnitude comet is too dim for the naked eye, but it is an easy target for backyard telescopes and digital cameras. (Aoshima used a Canon EOS 6D digital camera set at 12800 ISO for a 51x30sec exposure.) An ephemeris from the Minor Planet Center shows where to point your optics.
This is Comet Catalina's first visit to the inner solar system--and its last. The comet's close encounter with the sun in mid-November has placed it on a slingshot trajectory toward interstellar space. Enjoy it now. Once it recedes from Earth, we may never see it again. Browse the realtime comet gallery for more sightings.
