This is from Spaceweather. Not an observational event for us, but 2 asteroids so close to Earth in less than a month stirs the imagination. Great that we have better systems to detect these objects but I suppose it indicates just how little notice we might get if one were on a collision course.
PeterM.
"ASTEROID BUZZES EARTH: Newly-discovered asteroid 2009 FH is flying past Earth tonight only 85,000 km (0.00057 AU) away. That's a little more than twice the height of a geosynchronous communications satellite. Experienced amateur astronomers in North America can photograph the 20-meter-wide space rock racing through the constellation Gemini after sunset on March 17th. It should be about as bright as a 14th magnitude star. Please visit
http://spaceweather.com for an ephemeris and updates.
This is the second time in March that an asteroid has flown so close to Earth. On March 2nd, 2009 DD45 passed by only 72,000 km away. Measuring some tens of meters in diameter, 2009 DD45 and 2009 FH are approximately Tunguska-class objects, meaning they pose no global threat but could cause local damage if they actually hit Earth. In years past, asteroids of this size often passed unnoticed, but recent improvements in asteroid surveys have resulted in growing numbers of space rocks caught in the act of near-Earth flybys."
