红外天文观测中望远镜副镜的一种新调制方法

本文介绍一种称作三位调制的望远镜副镜调制新方法。在用望远镜作L和M波段的红外天文观测时,采用这种新调制方法,在一定条件下可以替代望远镜所做的双束转换运动而获得令人满意的结果。对于控制功能不是很强的望远镜,或者进行一些不允许望远镜摆动的特殊观测(如红外偏振测量),这种方法极为有用。本文介绍了这种新调制方法原理和电路,并且使用1.2米红外望远镜比较了用这种新调制方法和用通常的副镜二位调制方法对一组红外标准星的测量结果:在J和K波段;两种方法的结果大体相同,在L波段,新调制方法显示出明显的优越性。

A NEW MODULATION METHOD OF THE CHOPPING SECONDARY FOR INFRARED ASTRONOMICAL OBSERVATION

A new modulation method, called three phases modulation, of the chopping secondary for ihfrared observation is introduced in this paper. This new method can be used to replace the beam switch to obtain satisfactory results in the observations of L and M bands of the near infrared region. As for the teleseope whose automatic control level is not high enough to be provided: with the beam switch or when the beam switch of the telescope is not allowed in some special infrared observations, such as the infrared polarization measurement, this method will be considerably useful.This paper describes its basic principles, the electric circuit structure, the condition of operation and so on. Meanwhile a comparison is made between the results obtained by the new method and by the traditional two phases modulation of the chopping secondary. The results show that there are no great differences in J and K bands, but in L band the new method has an trangible advantage over the old one.