This earth-crossing asteroid flew by on the night of 17/18 August 2002. Literally. It moved at the rate of 8 arc minutes per minute, screaming through this 20 arcminute sqare frame in less than three minutes. The 500 meter diameter asteroid passed within about 500,000 km (320,000 miles) of the Earth. A near miss!
Imaged with an Andor CCD camera at Newtonian focus on the 24" Mather telescope, each exposure was approximately 1 second, with a three second interval between exposures.