DEPARTMENT OF MERIDIAN ASTROMETRY* 



Lewis Boss, Director. 



The headquarters of the Department of Meridian Astrometry is located at 

 the Dudley Observatory, Albany, New York. A branch observatory has 

 been established at San Luis, in the Argentine Republic, as described in the 

 reports of the Department for 1908 and 1909. 



The activities of the Department in the line of observation have been 

 wholly transferred to San Luis for the present. That station is in charge 

 of Prof. Richard H. Tucker, with Mr. A. J. Roy as chief assistant, and is 

 devoted to observations of far southern stars with the meridian-circle of the 

 Dudley Observatory, as described in previous reports. 



The work of the Department, as already stated, includes for the time being 

 no observations at Albany. During the past year operations at Albany have 

 been carried on mainly in three lines. 



a. Preparatory computation for the General Catalogue of Stars down to the seventh 



magnitude. 



b. Computations relative to the observations reported from San Luis. 



c. Publication of the Preliminary General Catalogue, preparation of a general cata- 



logue of standard stars for 1910, and studies upon systematic proper motion, 

 as derived from the individual values of motion contained in the Preliminary 

 General Catalogue. 



Under the first head, ephemerides for all the stars to comprise the pro- 

 posed catalogue of about 25,000 stars (which I call the General Catalogue) 

 are completed in such a manner that an accurate comparison of them with 

 the results of observation in each case can be readily made after the mate- 

 rial from the later observations becomes available for use. Much progress 

 has also been made in comparing the results of all published observations 

 with these ephemerides. 



Comment on the progress made under the second head — preliminary re- 

 ductions and tests of the observations made at San Luis — is deferred to a 

 later paragraph of this report. 



Under the third head it may be stated that the Preliminary General Cata- 

 logue of 6,188 stars was published in March 1910. The Department ac- 

 quired 200 copies, most of which have been presented to students of stellar 

 problems and to the principal observatories engaged in stellar observations. 

 Much of my personal attention has been given to the proof-sheets of this 

 work, which it was desirable to have specially free from errors. 



During the summer and autumn months of 1909, and in connection with 

 consultations with other members of the committee on proposed fundamental 

 observations desired by the Paris Congress of April 1909, a "List of 1,059 



* Address, Dudley Observatory, Albany, N. Y. Grant No. 605. $35,655 for investiga- 

 tions and maintenance during 1910. (For previous reports see Year Books Nos. 2-8.) 



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