加像场改正透镜的1.56米天体测量望远镜的天体测量检验

AN ASTROMETRIC TEST OF THE 1.56M ASTROMETRIC TELESCOPE WITH A SPHERICAL 2-LENS CORRECTOR

本文对1.56米天体测量望远镜的主光路R-C系统上加像场改正透镜后拍摄的底片,用天体测量标准星场:H.Eichhorn et al.的昴星团区域恒星精确位置作底片上星像位置的比较标准,在PDS上量测底片上的星像坐标,采用九常数、三次归算模型求得在底片中心士11’的像场范围内精度好于0."015,土18'的像场范围内达到0."020,在20cm×20cm(士23')的整个底片范围达到0."030的精度。底片常数中相应于彗差项系数达10^(-5)—10^(-6)量级,畸变项系数达10^(-9)—10^(-10)量级,比文[1]中在该望远镜主光路中不加改正透镜的相应值要小一个量级,这些结果表明,加像场改正透镜的该架望远镜的光学性能更为优秀。此外,本文还对各种底片归算模型的计算结果作了分析和讨论。

We have carried out an astromctric test of the 1.56 m reflector with a spherical 2-lens corrector of Shanghai Observatory. Three plates of the Pleiades region were taken and the images were measured with a PDS microdensitometer. Referring to the positions given in Eichhorn's catalogue as standards and using a cubic reductions formula, we find the positions within ±11' of the centre are determined with an accuracy of 0'.015, within ±18', an accuracy of 0'.02, and within ±23', an accuracy of 0'.03. In addition, the coefficient of the coma term in the plate constants is found to be on the order of 10^(-5)—10^(-6), and that of the distortion term, on the order of 10^(-9)—10^(-10) These figures indicate that the 1.56 m Astrometric Telescope with a spherical 2-lens corrector is very well fitted to undertake astrometric work of faint objects.