86 



place in a fow weeks. Mr. O. L. Petitid idler, of Chicaso. lias kiuilly loaned 

 the Observatory a paralnjlic mirror fifteen inches in diameter and with 

 a focal len;;th of 120 inches, which he constructed at h:s optical works. 

 The monntinft- for this mirror lias been desisned by Mr. W. A. C'ogshall 

 and in large part constructed by him. The reflector will be in place by 

 the first of March and will be used chiefly in photographing nebuhi?. 



These instruments, together with a portrait lens of Ave inches aperture 

 and a Browning e(iuatorial of four inches aperture, which for many years 

 have been the property of rhe University, constitute a nucleus aroiuid 

 which the University authorities hope to collect a more complete ecpiip- 

 men;-. 



The Observatory is located on rhe University campus, aliout HOO feet 

 from the nearest Itullding. With iiractically an unlii-okcn liorizon within 

 75 degrees of the zenith -as low as one can usually observe, and in most 

 instances the view is entirely unobstructed. 



We have found the seeing at tlie Observatory fair. On an average 

 clear night a i)o\ver of :i(io can Ik> used effectually; on about half the 

 working nights we use a power of 4S(f. wliile a night when a power of 

 more than (>()(> can be used is compai'atively rare. 



The Observatory is essentially a Students' Observatoiy. Those who 

 take covH'ses in general astronomy are permitted to use the telescope a 

 limited nunil)er of hours each week, and though this work is optional, few 

 fail to avail tliemselves of an ()i)p<irtiniity to use the telescope an hour. 

 No accurate measurements or really scientific work is attempted by these 

 students. 



In addition to tlie work in spherical and practical astronomy and 

 work carried on by the teaching force certain students are encouraged to 

 undertake woi-k in the nature of research. This generally consists of 

 drawing pl.anetary details or in making mlci'ometical measures of double 

 stars or of planetary disks. The oliserving lists are made out under 

 the direction of the Instructors and in general consist of stars that need 

 measuring. We are engaged at present iu measuring the double stars 

 discovered in the process of making the catalogues of the Astronomische 

 Gesellschaft. These as a rule are not dilflcult objects. Also search is 

 being made for ni>w pairs witli a fair degree of success. 



The Observatory liears the name of Dr. Daniel Kirkwood. tlie emi- 

 nent astronomer, who, for nearly half a century, was a meml)er of the 

 faculty of Indiana University and who, by his manly (luallties, won the 



