66 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1956 



cosmic rays, interplanetary gas, and radiation from without the solar 

 system. 



This broadened research program of the Astrophysical Observa- 

 tory now embraces not only research in solar activity and its effects 

 upon the earth, but also meteoritic studies and studies of the higher 

 atmosphere. New methods of research, as they develop, will be in- 

 cluded in the program. For example, radioactivity and nuclear 

 processes will be utilized in the study of meteorites. Theoretical 

 research and magnetohydrodynamics will increase our understanding 

 of how solar variations and activity occur and how the energy from 

 these activities affect the earth's magnetic field, produce air night 

 glow, the aurora borealis, and other phenomena of a geophysical 

 character. 



The new Satellite Program of the International Geophysical Year, 

 sponsored by the National Academy of Sciences and the National 

 Science Foundation, and in which the Astrophysical Observatory 

 has a very important part, promises a new and startling tool of re- 

 markable power in the study of solar-system and geophysical phe- 

 nomena. Such technological tools as may be developed will be in- 

 corporated in the working potential of the Astrophysical Observa- 

 tory. A restudy of plans and methods was an important first step. 



Work on solar radiation. — As reported last year, the quality of the 

 skies at the Montezuma station in Chile deteriorated to an intolerable 

 degree because of smoke introduced by smelting operations at nearby 

 copper mines. Consequently, the station was closed September 22, 

 1955. The scientific and new transportation equipment was moved 

 to Table Mountain in southern California. By the middle of winter 

 the three observers at that station, F. A. Greeley, A. G. Froiland, and 

 Stanley Aldrich, extended the observational program to include simul- 

 taneous observations of the sun from two similar arrays of radiation- 

 measuring equipment. In this fashion it will now be possible to check 

 the influence of instrumental variations upon the measurements of 

 solar radiation and atmospheric opacity. 



However, the Table Mountain skies are also beginning to show 

 progressive deterioration from the smog from the Los Angeles urban 

 area. So far this has not been too disadvantageous, but probably the 

 transparency loss will eventually necessitate the acquisition of a new 

 observing station for solar radiation. Serious searches for a site 

 with clear skies have been conducted in recent years, but the time is 

 approaching when a conclusive investigation must be made of the 

 usable high-altitude locations that offer the necessary atmospheric 

 qualifications for precise solar measurements. It is possible that the 

 use of satellite vehicles for carrying instruments to measure solar radi- 

 ation will eventually obviate the need for ground stations by elim- 



