The distortion solution for the 1-m telescope at Yunnan Observatory and its application to the positional measurement of four main-belt asteroids Eugenia(45), Roma(472), Lundmarka(1334) and Autonoma(1465)

Abstract

Four main-belt asteroids Eugenia, Roma, Lundmarka and Autonoma were observed at Yunnan Observatory 1-m telescope in 2022–2023. A total of 66 CCD frames for the four asteroids are observed. In order to improve the astrometry, the geometric distortion (called GD hereafter) of the 1-m telescope is solved. After GD correction, the precision of Eugenia and Autonoma has improved significantly and the standard deviation of the (O-C) residuals is improved by a maximum of 20 mas. The theoretical position of the asteroid is retrieved from the Jet Propulsion Laboratory Horizons system. Our results show that the mean O-Cs(observed minus computed) of the residuals is better than 0.1 arcsec in each direction. The dispersion is better than 0.071 arcsec in each direction.