Gehrels T
Lunar and Planetary Laboratory ofThe University of Arizona, Tucson, Arizona, USA.
Appl Opt. 1967 Feb 1;6(2):231-3. doi: 10.1364/AO.6.000231.
The ozone and oxygen in the earth's atmosphere prevent all ground-based observing at wavelengths shorter than about 3000 A. With the largest available balloons and a large telescope one can get sufficiently above the ozone to make precise polarization measurements of stars and planets near 2820 A and 2200 A. Two telescope/gondola systems are in operation. The first actually is a prototype for spacecraft but it is also used on balloons, mounted in a gondola of the National Center for Atmospheric Research. It has two 7.5-cm reflecting telescopes (7.5 cm is the diameter of the primary mirror). The second system has a 71-cm Cassegrain reflector, two vidicon cameras, command and telemetry by radio link, and a startracker that guides the stabilized platform (+/-1 min of arc). The first measurements made were of the polarization of the moon at 2900 A in December 1965, and of interstellar polarization at 2820 A and 2200 A in May 1966.
地球大气中的臭氧和氧气使得在波长小于约3000埃时无法进行地面观测。利用现有的最大气球和大型望远镜，可以升至足够高的高度以避开臭氧，从而对2820埃和2200埃附近的恒星和行星进行精确的偏振测量。有两个望远镜/吊篮系统正在运行。第一个实际上是航天器的原型，但也用于气球上，安装在国家大气研究中心的吊篮中。它有两个7.5厘米的反射望远镜（7.5厘米是主镜的直径）。第二个系统有一个71厘米的卡塞格伦反射镜、两个光导摄像管相机、通过无线电链路进行的指令和遥测，以及一个引导稳定平台（精度为±1角分）的星跟踪器。首次测量是1965年12月对2900埃处月球的偏振测量，以及1966年5月对2820埃和2200埃处星际偏振的测量。
