1108	 Digital Data Processor for Tracking the Partially Illuminated Moon	 A study of lunar tracking techniques and fabrication of a breadboard to assess the feasibility of the best technique selected was conducted to define a tracking system for observation of the sight line to the center of a partially illuminated moon. The data processing portion of the system is presented in detail and then described in general are the operation of the tracker head assembly for data readout the operation of the entire system and the effect data processing considerations have on the design of the tracker system. The system basically consists of an optical sensor digital computer and tracker drive mechanism. The three system units connected in cascade comprise the control loop. For this application an optical telescope with a radial mechanical scanning mechanism was used that read out lunar sight line measurement information. This information is sequentially read into a special purpose digital computer that extracts the measurements and computes the error signals that drive the tracker to the appropriate attitude.
