Abstract

In May and June, 1981, a 48-inch telescope located at the Goddard Space Flight Center Optical Test Site was used in conjunction with components of the University of Illinois sodium lidar system to make steerable lidar observations of the mesospheric sodium layer. Table 1 lists parameters of the steerable system. The telescope facility, located at 39.1°N, 76.8°W, consists of a 48-inch Cassegrain astronomical telescope with Coudé focus and supporting equipment which enables this instrument to be used in a variety of laser ranging experiments. The telescope aperture area is approximately the same as the objective area of the Fresnel lens receiving telescope used in Illinois. However, as well as making steerable measurements possible because of the sophisticated telescope mount, the high quality optics permit a small receiver field of view. This serves to reduce the noise counts due to background sky illumination.