The Experiment for the Application of Mutual Approximation Technique to High-precision Positional Measurement of Asteroid 702 (Alauda)

This paper extends the mutual approximation technique from positional measurement of natural satellites to a relative positional measurement of an asteroid and its nearby Gaia reference star, hoping to obtain a higher positional precision of asteroids. 1 m telescope at Yunnan Observatories of the Chinese Academy of Sciences is used to obtain the observations of the asteroid 702 (Alauda) on November 11 and 12, 2020. There are totally 5 approximation events of the asteroid with different reference stars in the observations. With reference to Gaia DR2 (Data Release 2) catalogue, our results show that in terms of accuracy, the mutual approximation technique is in good agreement with the classical CCD astrometry (i.e., a 4-constant plate model solution). The positional precision of the mutual approximation technique is 6 milli-arcseconds and 2 milli-arcseconds in right ascension and declination respectively, and the positional precision is improved obviously in compared with the classical CCD astrometry by a factor of 6-10.