DEPARTMENT OF MERIDIAN ASTROMETRY.* 



Lewis Boss, Director. 



The period covered by this report extends from September 191 1 to Sep- 

 tember 1912. 



OBSERVATIONS. 



The transit circle has been remounted. The instrumental tests applied 

 show that there is no appreciable change in the instrument, such as might be 

 caused by rough handling on its return trip from the southern station at San 

 Luis, Argentina. 



After the completion of the preliminary tests and final adjusting, observa- 

 tion was commenced on November 13, 191 1. While the past year has been 

 very unfavorable for observation, because of the excessive cloudiness, 9,715 

 observations have been taken, distributed as follows : A. J. Roy 4,703, B. 

 Boss 2,545, and W. B. Varnum 2,467. Because of continuous clouds, not an 

 observation was taken from December 29, 191 1, to February 15, 1912. The 

 same plan has been adhered to, of having each observer on duty continuously 

 for a week. 



The process of observing a group of stars in the afternoon and again in 

 the morning, in addition to the night observations, has been continued ; and 

 when possible successive transits of polar stars above and below pole have 

 been taken for an independent determination of the azimuth of the instru- 

 ment. 



In addition to the fundamental observations, the above summary includes 

 the observations of miscellaneous stars chosen in accordance with the pro- 

 gram already outlined for this Department. 



The usual determinations of magnitude-equation, of difference of transit 

 North minus South, of Chronograph minus Eye and Ear, etc., have been 

 included. 



In all the observations, circle B (opposite the clamp) was read, the dis- 

 tribution thus far being BE 4333, BW 5382. Four microscopes have been 

 recorded at each setting, the distribution of readings being as follows : 

 H. Raymond 4,744, S. B. Grant 4,528, and H. Jenkins 421. 



COMPUTATIONS UPON OBSERVATIONS. 



The computations have been mainly concerned with the reduction of the. 

 observations taken at San Luis, Argentina. 



* Address Dudley Observatory, Albany, New York. Grant No. 747. $26,316 for 

 investigations and maintenance during 1912. (For previous reports see Year Books 

 Nos. 2-10.) 



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