SATELLITE-TRACKING PROGRAIVI — HAYES 351 



Insofar as possible the Observatory wanted long-arc observations; 

 in other words, photographs that showed the satellite as it appeared 

 over the horizon, at culmination, and through to the other horizon. 

 AVliile the camera could track at variable speeds in order to match the 

 apparent motion of the satellite, it could not follow the same pattern 

 without changes in altitude of the line of sight. There were two 

 aspects to this problem : one, to predict the path ; the other, to have 

 the camera follow it. The observers improvised various means of 

 achieving these ends. 



When the camera followed the motion of the satellite, the satellite 

 image on the film would appear as a pinpoint and therefore might be 

 very difficult to find. The observer soon discovered that elongated 

 images could be obtained just by holding the shutter open and jig- 

 gling the mechanism a little bit. By this means they had their first 

 real opportunity to detect faint satellite images. 



Since some of the predictions were not accurate, the observer often 

 had to pattern the sky for the satellite ; that is, he would scan the sky 

 with a camera, making changes of altitude and other corrections, 

 hopping by this means to catch the satellite. 



After the film was developed, the observer had to identify the posi- 

 tion of the satellite image among the stars. The staff of the Harvard 

 Meteor Project in New Mexico had literally memorized the night sky. 

 When, using the super-Schmidt, they photographed a satellite pas- 

 sage, they made a mental note that it went 2° south of the star Fomal- 

 haut. They then took out the CD star chart and fitted the field against 

 that of the film. 



The new observers of the Smithsonian program had no such knowl- 

 edge and experience, so they had to find other means of identifying 

 the star field quickly. Tables were prepared for rapidly converting 

 azimuth and altitude, known sidereal time, and even the right ascen- 

 sion and declination, on a star chart. Also mechanical means such as 

 a navigation globe were developed. 



At first obsen^ers would spend as much as 9 or 10 hours identifying 

 the star field. As the satellite load increased, this became an im- 

 possible procedure. Each station developed its own particular tech- 

 nique for identifying the star field, and only much later would these 

 be standardized to a common procedure. 



Finally, most of the stations had some problems with the power 

 supply to the Norrman clock and the slave clock. At the New 

 Mexico, Florida, Hawaii, and South Africa stations there were only 

 small and infrequent fluctuations of power in the commercial line, 

 and few power failures. At the other oversea stations, however, the 

 voltage fluctuations were often quite considerable so that the time 

 presentation of the slave clock would vary considerably. When the 



