12 ATSTNTJAL REPORT SMITHSONIAN INSTITUTION, 1963 



servation of animals, lias also been carried on with increasing success 

 during this 10-year period at the Zoo. 



Astrophysical Observatory, 1953-63 



During the decade ending in 1963 the Smithsonian Astrophysical 

 Obsei-vatory experienced greater change and generated more scientiiic 

 data than in any other comparable period since its establislmient in 

 1890. In the decade the staff has increased to over 300 members. 

 Its publications include 130 special scientific reports, plus 7 volumes 

 of a new scientific series, Smithsonian Contributions to Astrophysics. 



At the beginning of the decade the Observatory maintained tw^o 

 high-altitude stations for solar observations : the resultant data were 

 used to determine the solar constant and to relate it to atmospheric 

 phenomena. Tliis important gromidbreaking study was discontinued 

 in 1962 because the method had reached the limit of usefulness. 



When Loyal B. Aldrich retired as Director in 1955, Dr. Fred L. 

 Whipple was appointed his successor, and in fulfillment of an arrange- 

 ment with Harvard University the Observatory was moved to Cam- 

 bridge, Mass., where it has gained much from close association with 

 the large number of scientific research workers in that area. 



The following year the Observatory received, through the Smith- 

 sonian Institution in Washington, the first of a series of grants from 

 the National Academy of Sciences and the National Science Founda- 

 tion for the optical tracking of artificial earth satellites to be launched 

 during the International Geophysical Year. At the end of the IGY 

 in 1959, the resultant tracking program of the Observatory continued 

 under a grant from the National Aeronautics and Space Administra- 

 tion. The tracking camera was designed to achieve a position accu- 

 racy of 1 second of arc, and a time accuracy of 1 millisecond in photo- 

 graphing satellites. In addition, there were organized a Moonwatch 

 program of amateur astronomers to make preliminary observations 

 of satellites, a computations division to prepare orbital predictions 

 and ephemerides, and a communications network to tie together the 

 tracking headquaiters in Cambridge with the camera stations, the 

 volunteer Moonwatch teams, and other Government agencies. 



When Sputnik I was launched on October 4, 1957, the first camera 

 had been completed, the Moonwatch teams were ready to begin visual 

 observing immediately, and orbital calculations and predictions com- 

 menced. In the next 9 months 12 Baker-Nunn cameras were com- 

 pleted and shipped to stations established by the Smithsonian Ob- 

 servatory in Japan, Australia, South Africa, India, Iran, Spain, 

 Peru, Argentina, and the Netherlands West Indies, as well as in 

 Florida, New Mexico, and Hawaii. 



By the end of the decade the Moonwatch teams had made more than 

 53,000 observations of 191 different satellites and the cameras 81,750 



