SATELLITE-TRACKING PROGRAM — HAYES 



311 



CLAMP 



TOP VIEW 



EYEHECE 



STRAP 



END BRACKET 



FRONT-SURFACE 

 MIRROR 



CROSS-SECTION VIEW 



ACHROMATIC 

 7^ /LENS 



^^CLAMP 



ALUMINUM PIPE 



ERFLE EYEPIECE 



Figure 4. — Schematics of 50-mm. Moonwatch monoscope. 



against a background of stars and on the meridian pole in the line 

 of sight of tlie telescope. The group leader would then send the 

 information to the communications center in Cambridge. 



The program had three major teclmical problems. The first was 

 that of precise timing of the observations. This could be done by 

 use of either a stopwatch or a chronogi'aph checked against accurate 

 short-wave radio time signals broadcast by "WWV or by some other 

 national time service. The second was the accurate recording of the 

 satellite position against the backgroimd of stars. For this purpose 

 copies of the Skalnate Pleso Atlas of the Heavens were distributed to 

 the teams. The third technical problem, of course, was the choice of 

 a suitable telescope; the instrument had to be able to pick out objects 

 of the 7th or 8th magnitude ; and it had to be of simple, rugged de- 

 sign so that it could be easily used and would prove durable through- 

 out the life of the program. 



To determine the specifications of the telescope and the organiza- 

 tional details of the typical team, G. R. Wright, chairman of the Na- 

 tional Advisory Committee, established a pilot Moonwatch station at 

 his home in Silver Spring, Md. There a group of amateur astrono- 

 mers tested some 30 different optical instruments that had been pro- 

 posed for visual tracking. Three of these instruments ^^ met ad- 

 mirably the needs of the program, and from them the Observatory 

 drew up the specifications for what was to become known as the Moon- 

 watch monoscope; the eyepiece was a wide-angle Erfle of 1.25-inches 



" BuUt by Roy Walls of Washington, D.C., by Arthur S. Leonard of Davis, Calif., and 

 by Roy M. Griffing of Los Altos, Calif. 



625325—62- 



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