PHOTOGRAPHY IN THE SERVICE OF ASTRONOMY.* 



J>.V R. Radau. 



Translated by Aaron N. 8kinnek, f". S. Kara! Ohnerratov]! . 



To obtain tbe greatest result with the least effort, is not this the 

 whole problem of luodorii industry, a proltlein which determines gradu- 

 ally the de.veloi)ment of imj^lemeuts and machines ? The engines which 

 he invents permit man to infinitely multiply the efficiency of his organs, 

 to extend their fitness, and to relieve them from the demands of exces- 

 sive efforts; they assist him, free him, more and more from the harsh 

 servitude of material labor. Confining himself henceforth to oversee- 

 ing the apparatus which labors for him, in proi)ortion as he fatigues 

 himself less, he produces more and at mucli better advantage. There 

 is no comparison between the fabrication of a thousand needles from a 

 manufactory, and the work of an artisan who undertakes fashioning 

 them one by one by his owji unaided efforts. 



It is a progress of the same order which realizes to-day thedelinitive 

 introduction of photography in astronomical observations: It is to 

 deliver the astronomer from a labor, thankless, painful, irksome, and 

 fatal for the e3es. When ten years ago I spoke in this jouriuil of the 

 great prospects of celestial i)hotography t I dared scarcely to hope that 

 routine and prejudice Avould be disarmed so speedily. Indee^l the 

 first attempts in astronomical i)hotography go as far back as 1840, and 

 during nearly half a century fre(iuent attempts, unhappily always iso- 

 lated, have shown that the difficulties of the problem have not been 

 insoluble; but on account of tenacious i)rejudi<'es, a blind adherence to 

 the past proscribed the parai)hernalia of photography from the sanctu- 

 aries or kept up the traditions of Cassini and of Bradley. It is in 

 these later years that fimilly this si)ontancous enthusiasm ai)peared, this 

 grand movement whi(di has found its ex])r(!Ssion in the "Astro-jjlioto- 

 graphic Congress," convened in Paris in the month of Ai)ril, 1887, and 

 which promises to begin a work of the highest importance for future 

 ages, the photographic execution of a general chart of the sky. 



* From the Kcviie (Jes Deux Mondes : April I, 1889, vol. xcii, pp. ()'2()-(My. I.— E. 

 MoucIr'z, "Astrononiiciil Plioto^rapliy at the Paris Observatory and the chart of tlie 

 sky," Paris, 1887. II. — bulletin of the Perniauent International Committee for tiio 

 execntion of the photojriapliic chart of the sky, 1888, 1889. 



\ lievue des Deux Mondes of February 15, 1878. 



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