The recovery of near-Earth asteroids

A very important step for the acquisition of accurate orbital information of near Earth asteroids (NEAs) is the recovery process. About one-third of the known NEAs have been observed for more than one opposition. We studied the circumstances of the recovery of all NEAs with atleast two oppositions and found that there are several ways to find observations of a different opposition from that of the discovery. We divided all the recoveries into four different classes. Following the observations at the new opposition, we concluded that planning observations at the telescope is still the best way to hope to observe NEAs at a new opposition. At the same time we reached the conclusion that a large number of NEA observations are still to be found in existing archival astronomical records. (C) 2000 Elsevier Science Ltd. All rights reserved.