Proceedings, &c., for 1887. J).*} 



Society. Also a copy of the Illustrated Handbook of Victoria, 

 issued by the Victorian Commissioners at the Exhibition. 



Mr. Ellery then read a note "On the Proposed Photographic 

 Charting of the Heavens." He said that for some years, 

 photography had been a very useful hand-maiden to astronomy. 

 Since the introduction of the rapid gelatine plates, the utility of 

 photography in that direction had been immensely increased. 

 Very greatly improved photograplis of comets and other heavenly 

 bodies could now be taken under that process. During the last 

 three or four years, too, immense strides had been made in the 

 direction of charting the stellar heavens. In Paris particularly 

 they had made great progress in that direction. By means of 

 special telescopes at the Paris Observatory, they had obtained 

 charts of stars down to the 14tli magnitude that had astonished 

 everyone who had seen them. Last year a circular was sent from 

 the Paris Observatory, intimating that a conference was to be 

 held at Easter this year of all astronomers who could attend, to 

 consider as to the best means of carrying out a scheme for the 

 complete photographic chart of the heavens. As Mr. Pussell, 

 Government Astronomer of New South AYales, had determined to 

 go to the old country about that time, he (Mr. Ellery) did not think 

 it necessary to accept the invitation. The conference was held, and 

 it decided that this great work should be carried out. But there 

 were in the sou.thern hemisphere only a very few observatories, 

 compared with the number in the northern hemisphere. Indeed, 

 the number was so few, that it was considered doubtful at first 

 whether the scheme could be efiectively carried out. It was 

 estimated that the cost for each national observatory would be 

 about £4000 for instruments and appliances. The work would 

 extend over some years. At the conference Mr. Pussell expressed 

 his opinion that the co-operation of the Melbourne and Sydney 

 Observatories might be considered assured. He (Mr. Ellery) laid 

 the matter before the Government, and the Government quite 

 concurred in the proposal. He believed that the Melbourne 

 Observatory would take its part in the scheme. Two new 

 observatories were wanted for the purpose, one in the Island 

 of Beunion, and the other in the southern part of New Zealand. 

 Nearly all the present observatories in the southern hemisphere 

 were in similar latitudes, and if observatories were established at 

 the places just mentioned, a little more ground could be covered. 

 It had been found that stars down to the 15th and 16th magnitude 

 could be obtained on a photographic plate by exposure for one or 

 two hours. The smaller the star, the longer the exposure must be. 

 To get photographic pictures of stars during that period, the 

 telescope must be kept moving with the apparent movements of 

 the stars. For that purpose, a clockwork arrangenxent was 

 necessary, and of such a perfect character as to be scarcely 



