APPENDIX 8 



REPORT ON THE ASTROPHYSICAL OBSERVATORY 



Sir: I have the honor to submit the following report on the op- 

 erations of the Astrophysical Observatory for the fiscal year ended 

 June 30, 1945 : 



The work of the Astrophysical Observatory is conducted on funds 

 received largely from appropriation by Congress, amounting for the 

 fiscal year 1945 to $44,140, and in part from private sources. There 

 are two divisions : 



( 1 ) DIVISION OF ASTROPHYSICAL RESEARCH 



This division has its headquarters in Washington, and maintains 

 three field stations for solar observations, at Table Mountain, Calif., 

 Tyrone, N. Mex., and Montezuma, Chile. In Washington the di- 

 vision occupies frame buildings in an enclosure about 15,000 square 

 feet in area just south of the Smithsonian Building. The frame 

 structures have served for many years as the offices and laboratories 

 of the division. During the fiscal year 1945 extensive alterations and 

 repairs were made which provide greatly improved facilities for the 

 work of the division. 



Work at Washington. — In the first half of the fiscal year a large part 

 of the time of Mrs. Bond, Mr. Hoover, and the Director was given 

 to a compilation of all solar-constant values for the period October 

 1939 to January 1945. This compilation is an extension of the great 

 table (table 24) of volume 6 of the Annals of the Astrophysical Ob- 

 servatory. The extended table summarizes the important factors 

 employed in the reductions and also gives the preferred solar constant 

 for each day of observation in the 21^-year period July 1923 to 

 January 1945. Inasmuch as this period includes three sunspot 

 minima (July 1923, September 1933, May 1944), and thus covers a 

 complete double sunspot period, it became of interest to study all these 

 results to determine what relationship exists between solar constants 

 and sunspot numbers. A paper summarizing this study (Smithsonian 

 Misc. Coll., vol. 104, No. 12) shows a diametrically opposite relation- 

 ship between solar-constant values and sunspot numbers in the two 

 halves of the double sunspot period. It is important to discover in 

 the succeeding cycle of sunspots whether this complex relationship 

 will repeat itself. If so, the prediction of solar variation as given in 

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