Report on the Astrophysical Observatory 
Sir: I have the honor to submit the following report on the opera- 
tions of the Astrophysical Observatory for the fiscal year ended June 
30, 1958: 
The Astrophysical Observatory includes two research divisions: 
the Division of Astrophysical Research, for the study of solar and 
other sources of energy impinging on the earth, and the Division of 
Radiation and Organisms, for investigations dealing with radiation 
as it bears directly or indirectly upon biological problems. Shops— 
for metalwork, woodwork, and optical electronic work—are main- 
tained in Washington to prepare special equipment for both divisions, 
and a shop for high precision mechanical work at Cambridge. <A field 
station for solar observation is located at Table Mountain, Calif. 
DIVISION OF ASTROPHYSICAL RESEARCH 
The most important event of the past year was the activation of the 
Optical Satellite Tracking Program, within two hours of the launch- 
ing of the first artificial earth satellite on October 4, 1957. The 
resulting data have already produced vital new information about 
the density and temperature of the upper atmosphere and the earth’s 
equatorial bulge. The exploration of space by manned and unmanned 
space vehicles continues to receive study, and specific plans have been 
formulated for placing an astronomical telescope in a satellite orbit. 
The Observatory has pursued its investigation of solar-system phe- 
nomena, particularly of cosmic gas dynamics and celestial mechanics}; 
and studies of the origin, structure, and probable age of meteorites 
have continued. 
The close liaison between the Astrophysical Observatory and the 
Harvard College Observatory, the Massachusetts Institute of Tech- 
nology, and other research centers in the Boston area continues to 
bring mutual benefit. Its long-term goal, to make crucial astronomi- 
cal observations and experiments above the atmosphere, is well on the 
way to realization. 
Solar astrophysics—At the Table Mountain Station, Alfred G. 
Froiland has been measuring atmospheric ozone, to determine the 
light absorption of ozone in a vertical path, both in the visible spectral 
range and in the infrared, from a single spectrobologram; and also, 
possibly, to measure the quantity and quality of haze. This study 
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