London: Taylor and Francis, 1862. 1st Edition. FIRST EDITION COMPLETE EXTRACT FROM THE PHILOSOPHICAL TRANSACTIONS (WITH PLATES) OF DE LA RUE’S BAKERIAN LECTURE PRESENTING HIS GROUNDBREAKING ASTRONOMICAL PHOTOGRAPHY OF THE SOLAR ECLIPSE OF 1860. Included are thirteen de la Rue’s plates, among them are some of the most famous images of the Sun ever rendered. de la Rue’s efforts constituted “the first systematic application of photography to a solar eclipse” (Bray, Plasma Loops, 2). The photographs he produced “were the first to definitively demonstrate that the corona seen around the moon during a solar eclipse is a phenomenon associated with the sun rather than the moon” (Davidson, Warren de la Rue, 2). There had been much scientific debate as to the nature and origin of the red flames visible at the edges of the moon during an eclipse. De La Rue’s photographs firmly established the exclusively solar character of the red flames, now known as prominences, and de la Rue is credited with their discovery.
Warren de la Rue was a British chemist and astronomer whose efforts “helped make photography one of astronomy’s greatest tools” (Stanford Solar Center). de la Rue adapted wet plate photography to lunar photography, pioneering “the application of photography to the study of the Moon and Sun [and] in the process demonstrating the value of an equatorially mounted, clock-driven reflecting telescope as a camera, techniques that greatly accelerated the evolution of the new science of astrophysics” (Biographical Encyclopedia of Astronomers, 284).
In the mid-19th century, John Herschel spoke openly about the importance of a daily photographic record of sunspots. In 1854 and at Herschel’s urging, the Royal Society granted support to de la Rue to invent a telescope specifically designed for photographing the Sun. de la Rue did just that. His invention, the photoheliograph, was the first astronomical instrument constructed for the photography of celestial objects [and it is described in detail in this paper]. Known as the Kew Photoheliograph, de la Rue’s instrument included an achromatic objective, a clockwork mechanism, and a Huygenian eyepiece (one actually constructed by Huygens in the 17th century and presented to the Society by Newton). In 1860 de la Rue took his invention at his own expense on an expedition to Rivabellosa Spain with the hope of photographing a total solar eclipse to occur on July 18th. The photographs de la Rue took represent the first extended series of photographic observations of the Sun over a solar cycle.
As de la Rue prepared his report for the Royal Society, presented in this paper, George Airy insisted upon the import of reproducing the original photographs without any alteration whatsoever. Airy believed that photography could standardize observation and argued that “exact facsimiles of the two eclipse photographs [were] infinitely more important than composites or retouched plates” (Pang, Empire and the Sun, 93). “De la Rue made two facsimile engravings of his photographs but it was very difficult work. Just copying the photographs took months: it was ‘tolerable easy’ to make copies ‘which show the results fair well’ when examined by eye, but copies for reproduction had to be stronger and more carefully made” (ibid, 94). The two facsimile engravings are included among the 13 de la Rue plates, a number of which are also hand-colored. Item #837
CONDITION & DETAILS: London: Taylor and Francis, Printers to the Royal Society. Complete extract. (11.5 x 9.25 inches; 288 x 231mm). pp. 333-416; In-text illustrations throughout; 14 plates, 4 large fold-out. Bright and clean throughout the text. The plates are somewhat toned at the margins. Very good condition.