Sur les photographies de la Lune obtenues au grand Équatorial coudé de l'Observatoire de Paris [Part I] in Comptes Rendus, Vol. 119, No. 2, pp. 130-135, 9 July 1894 AND Sur les photographies de la Lune obtenues au grand Équatorial coudé de l'Observatoire de Paris [Part II] in Comptes Rendus, Vol. 119, No. 4, pp. 254-259, 23 July 1894. Pierre Henri Puiseux, Maurice Loewy.

Sur les photographies de la Lune obtenues au grand Équatorial coudé de l'Observatoire de Paris [Part I] in Comptes Rendus, Vol. 119, No. 2, pp. 130-135, 9 July 1894 AND Sur les photographies de la Lune obtenues au grand Équatorial coudé de l'Observatoire de Paris [Part II] in Comptes Rendus, Vol. 119, No. 4, pp. 254-259, 23 July 1894

Paris: Gauthier-Villars, 1894. 1st Edition. ORIGINAL WRAPS, FIRST EDITIONS OF TWO PAPERS (July 9, 1894 & July 23, 1894) IN WHICH THE FRENCH ASTRONOMERS PIERRE HENRI PUISEUX AND MAURICE LOEWY DETAIL THE PIONEERING WORK THAT LEAD TO THEIR SEMINAL LUNAR ATLAS, A WORK REGARDED AS 'THE ULTIMATE ACHIEVEMENT OF NINETEENTH-CENTURY ASTRONOMICAL PHOTOGRAPHY" (The Photobook: A History, Vol. I, p. 54). Note that these rare papers precede in publication the atlas itself (the first installment of which did not come out until 1896).

In July of 1894 and in the first of these two papers, Puiseux, Loewy, and the French Academy of Sciences announced a massive "project aimed to make the first complete large-scale photographic atlas of the moon; it was a project that succeeded far beyond anyone's hopes and their results astounded both the scientific and artistic communities. Earlier attempts at photographing the moon had suffered from difficulties with the sensitivity of collodion emulsions and with atmospheric 'blurring'" (E. A. Whitaker, Mapping and Naming the Moon, 151).

Together, these papers detail not just the scientific work and instrument design and adjustment that enabled their project, but also discuss "the subject of lunar photography and the difficulties which must be overcome in order to realize the full capabilities of the apparatus at their command" (The Astrophysical Journal, Vol. 5, 52). An interesting aspect of their instrumentation design "is the method which they use for getting rid of the motion of the image in declination, by choosing for exposure times when the Moon's motion in declination is neutralized by the change of parallax. The rate of the driving clock is controlled by the observer, without stopping the clock, by means of a sliding weight on the pendulum. In some places the authors give the conclusions to which they have been led, by a study of their photographs, as to the nature and probably origin of the characteristic features of the Moon's surface" (ibid).

Another technical hurdle related to instrument design was the fact that the images Puiseux and Loewy took would need eventually to be printed for the atlas. "Operating at the end of the 19th century, photographic printing techniques had improved enough that the next logical step for Puiseux and Loewy was to get achieve a magnification similar to that achieved by selenographers (existing photographic telescopes had a plate size of 2-3 inches). Toward this end, Loewy and Puiseux designed and used a 'novel' telescope with a plate size of 7 inches in diameter that could be enlarged 8-15 times. Over the duration of the project they took more than 6000 photographs. Weather restrictions meant they had 50-60 days a year that were clear enough to photograph, and of those sessions only four or five negatives would be good enough to use" (Whitaker).

Loewy didn't live to see the project completed, but when the atlas was finally finished in 1910, it was described as a "scientific and aesthetic tour de force of lunar photography" and remains heralded to this day (Thomas, Beauty of Another Order: Photography in Science). Item #1010

CONDITION & DETAILS: Paris: Gauthier-Villars. Two issues, each in original paper wraps. 4to. [11.25 x 9 inches]. Slight edge wear and fading to the wraps of each issue. Minor. The interior is evenly toned and clean. Very good condition.

Price: $1,350.00