M. Kocer, J. Ticha, and M. Tichy
Klet' Observatory, Zatkovo nabrezi 4
CZ-370 01 Ceske Budejovice, Czech Republic
Abstract. The number of known Near-Earth Asteroids (NEAs) has rapidly increased in recent years due to LINEAR and other large surveys (Spacewatch, LONEOS, NEAT and CSS). This discovery process has to be folloved by follow-up observations to obtain a sufficient number of precise astrometric data needed for an accurate orbit determination of newly discovered bodies. About forty per cent of the known NEOs have been observed for more than one opposition. This follow-up process starts by confirmatory observations and continues over a sufficient observing arc in the discovery apparition. Accurate orbit determination requires observations from at least two oppositions. If asteroids are not found in the next apparition, different from the discovery one, then they can be considered lost. This is particularly embarrassing for NEAs. Therefore NEA recovery is a very important part of NEA follow-up astrometry. If data for different apparitions are not find in the course of precovery surveys or in other achive data, then it is necessary to prepare targeted observations of a particular NEA in the second convenient apparition. We discuss here methods, techniques and results of planned recoveries at the Klet' Observatory using 0.57-meter telescope equipped with a CCD detector. We also mention the overall work on NEA recoveries provided by several NEO follow-up programmes as well as a need for communication resources supporting astrometric observers. Finnaly we present here a planned extension of Klet' NEA recovery subprogramme to fainter objects by means of larger 1-m~telescope, which is being built at Klet' now.