had ever seen ; while testing it Alvan Graham had discovered the com- 

 panion of 1 02 Herculis and the elongation of the principal star of I Sagit- 

 tae. 77 Draper mounted this telescope on the same equatorial stand with 

 his 28-inch silver-on-glass reflector and compared the performances of the 

 two instruments; the photographs taken with each were of about equal 

 clarity. In 1880 this refractor was turned in on a newer model; it was 

 subsequently sold to the Lick Observatory (q.v.) where, in the hands 

 of E. E. Barnard, it yielded exquisite photographs of comets and nebulae. 



The newer model was an 1 1 -inch triplet — a visual achromat with a 

 photographic correcting lens — which the Clarks had made for the Lisbon 

 Observatory (q.v.). Its equatorial stand and driving clock were made 

 by Draper himself. With this instrument, on the evening of 30 September 

 1880, Draper took the first successful nebular photographs. His pictures 

 of the bright part of the Orion nebula, in the vicinity of the trapezium, 

 showed "the mottled appearance of this region distinctly." 78 After 

 Draper's death his widow made the 1 i-inch available to the astronomers 

 at Harvard (q.v. ) as part of the Draper Memorial study of stellar spectra. 



During the solar eclipse of 29 July 1878 Henry Draper photographed 

 the corona with a telescope of 5 inches aperture and 78 inches focal 

 length, corrected for photography by the Clarks. 79 



By 1863 the Dudley Observatory, in Albany, New York, had a 

 Clark comet seeker of 4 inches aperture and 42 inches focal length. It 

 was equatorially mounted and supplied with right ascension and declina- 

 tion circles of 5 inches diameter. 80 



When Lewis Boss was appointed director of the Dudley Observatory 

 in 1876 he found most of the instruments in need of repair. As soon as 

 possible, therefore, he engaged the Clarks to bring the apparatus to a 

 "state of efficiency." In his annual report of 1877 Boss had noted that it 

 was "well known that the thirteen-inch equatorial by the late Henry Fitz 



77 Edward S. Holden, Obituary of Alvan Clark, San Francisco Daily Examiner, 

 20 August 1887, p. 1. Alvan Clark to Edward S. Holden, 8 March 1876 (letter in 

 Lick Observatory Archives). 



78 Henry Draper, "Photographs of the Nebula in Orion," American Journal of 

 Science, vol. 20 (1880), p. 433. 



79 Henry Draper, "The Total Solar Eclipse of July 29th, 1878," Journal, Franklin 

 Institute, vol. 106 (1878), pp. 217-220. 



80 Report of the Astronomer in Charge of the Dudley Observatory (1863), pp. 4, 10. 

 See also Annals, Dudley Observatory, vol. 1 (1866), p. 24. 



58 



