应用Gaia DR1的木卫六天体测量试验观测

Experimental Astrometry of Himalia using Gaia DR1

木卫六是木星最大的一颗不规则天然卫星,为了获得它的高精度观测位置,天体测量归算过程中各方面都需要考虑,其中特别重要的是参考星表的选择。应用最新公布的星表Gaia Data Release 1(Gaia DR1),同时采用UCAC4星表进行比较,对2015年云南天文台获得的185个木卫六的观测资料进行处理和归算,结果显示,采用Gaia DR1星表的木卫六的位置测量精度在赤经和赤纬两个方向都约为0.02″,比采用UCAC4的结果有显著提升。

Himalia is the largest member of Jovian irregular satellites. In order to obtain its high-precision observed positions, all the astrometric effects in data reduction should be taken into account, especially for the star catalogue used. In this paper, the newly published star catalogue Gaia Data Release 1 （Gaia DR1） was used to math reference stars in all CCD frames. In order to make comparisons, the catalogue UCAC4 was also used in data reduction. A total of 185 CCD observations of Himalia were processed. Our results showed that the positional precision of Himalia is estimated at about 0. 02＂ in both right ascension and declination, after catalogue Gaia DR1 was used. This precision is significantly improved than the results by using catalogue UCAC4.