288 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1961 



whereby the camera would alternate between remaining stationary 

 and tracking the satellite. After many discussions, they chose the 

 third method because it offered both greater flexibility of tracking 

 technique and an extra margin of safety, ensuring that the camera 

 could record a faint satellite as Vv'ell as the star background. 



Mr. Nunn made a set of preliminary drawings and sent them on to 

 Cambridge. To indicate the real size of the device, an isometric 

 presentation showed a 6-foot man standing next to the camera, which 

 was approximately 12 feet high and about 12 feet long at its greatest 

 horizontal dimension. The shoulders of the operator shown at one 

 end of the camera came about IcA^el with the normal pivot point of 

 the camera itself. It would be, then, a fairly large instrument. 



The third requirement of the system was some means of timing the 

 satellite observations. In the spring of the previous year Kobert 

 Davis, a graduate student at Harvard, had worked with Dr. Whipple 

 in planning a timing system for Project Orbiter and in outlining 

 techniques for tracking satellites. They had determined that they 

 would need a position accuracy of abovit 1 or 2 seconds of arc with a 

 reasonable but versatile camera, and this would in turn demand an 

 accuracy of approximately 1 millisecond in the timing of the observa- 

 tions. After some investigation Mr. Davis ordered a model 110 

 frequency time standard from Norrman Laboratories in "Williams 

 Bay, Wis. 



In February 1956 the Norrman time standard arrived in Cambridge. 

 Packed in a cardboard box for shipping, it had been handled so 

 roughly in transit that four of the control knobs had been broken 

 and some other damage done. Nevertheless, when plugged in, it 

 worked, giving Mr. Davis a certain confidence in its ruggedness and 

 reliability. In the weeks that followed he tested the clock to prove 

 that, in Cambridge at least, it would keep time to within a millisecond, 

 although its performance in the field was an uncertainty. 



The next question was, where should the Baker-Nunn camera sta- 

 tions be located? The Vanguard satellites were planned for low 

 inclinations in respect to the Equator, and the stations had therefore 

 to be in a broad band defined roughly by the 30th parallels north and 

 south. To this requirement was added the concept of a north-south 

 line of stations in the Western Hemisphere. Furthermore, the loca- 

 tions had to be where there was a minimum of cloud cover and where 

 the landscape would permit observations of satellites reasonably near 

 the horizon. Finally, the overseas sites had to be in countries with 

 which it would be possible to make agreements for the establisliment 

 and maintenance of the stations. 



Since astronomers form a closely knit international fraternity, 

 Hynek's plan was simply to correspond with astronomers he knew 



