Last months image showed the motion of the Near Earth Asteroid 2002 NY40 in a sequence of short exposures. In the images below, the rapid motion of the asteroid is apparent by the long trails seen in the two 60 second exposures. The earlier (left) image was taken on August 17, 2002, at 21:30 UT, the later (right) image on August 18, 2002, at 01:54 UT. In the 4 hours and 24 minutes between the exposure, the distance between the asteroid and the observer decreased from 0.0062 A.U. (927.000 km) to 0.0046 A.U. (688.000 km), while the apparent motion increased from 164 arc seconds per minute to 316 arc seconds per minute, resulting in a trail that is nearly twice as long in the second exposure than in the first.
Asteroid 2002 NY40, imaged on August 18, 2002, by Markus Griesser, Eschenberg Observatory, Winterthur, Switzerland. The two 60 second exposures were taken with a Apogee AP-7p CCD on a 0.40m f/5.9 Hypergraph. Only a quarter of the original images, 512 x 512 pixels in size, is shown here.