Appendix A to Report of Committee on 



Observatories 



report by w. j. hussey on certain possible 

 sites for astronomical work in 



CALIFORNIA AND ARIZONA 



Prof. Lewis Boss, 



Chairman Astronomical Committee, Carnegie Institution. 



Sir : Acting under your instructions, I left San Jose for southern 

 California on April 16, 1903, to examine into conditions for astro- 

 nomical work in that section, especially with reference to research 

 upon the sun. I was to bear in mind the following requirements : 

 First of all, excellent day seeing ; scarcely second to this, excellent 

 night seeing ; fitness of site for living conditions, accessibility, 

 availability of power, electric or other, either from abundant water 

 sources or from commercial distribution, etc. 



For the purposes of this survey, a 9-inch achromatic objective, 

 focus 108 inches, was kindly loaned to the Committee by the Alvan 

 Clark and Sons Corporation. The Lick Observatory loaned a War. 

 ner and Swasey micrometer, a declination axis and slow motion by 

 the same makers, a good centrifugal driving clock, and many smaller 

 pieces of apparatus needed in this work. A prism-and-grating spec- 

 troscope was loaned by the Chabot Observatory, and an excellent 

 helioscopic eyepiece was supplied by the Yerkes Observatory. 



The mounting of the telescope was made in the Lick Observatory 

 instrument shops from my designs. Its general features will be 

 understood from the accompanying photographs.* It was expected 

 that tests in out of the way places would be required, and on this 

 account the mounting was made as light as was consistent with 

 sufficient rigidity, and the parts were so arranged that they could 

 be transported on pack animals over mountain trails. The tube is 

 constructed of aluminum sheets one sixteenth of an inch thick, suit- 

 ably strengthened by end and center castings, etc. Its weight, 

 complete with lens, tail piece, micrometer, and counterweights, is 

 only 88 pounds. The wooden polar axis is provided with steel 

 trunnions which turn in roller bearings. 



* Not here reproduced. 

 (71) 



