1900-1978

Ritchey, George Willis (1864-1945).

"Celestial photography with the 40-inch visual telescope of the Yerkes Observatory," in: The Astrophysical Journal, – vol. 12, pp. 352-360 and plate XXI, "Lunar Crater Theophilus and Surrounding Region." – Chicago: The University of Chicago Press, 1900.

G.W. Ritchey was perhaps the most skilled lunar photographer of the early twentieth century. Working with the 40-inch refractor at the Yerkes Observatory, he was able to capture details in his negatives that evaded the efforts of his colleagues at the Lick and Paris Observatories. Ritchey's photographic work was so superior that sixty years later, when G.W. Kuiper and his colleagues were assembling the monumental Photographic Lunar Atlas (see item 32), and had thousands of more recent photographs to choose from, they still elected to use three of Ritchey's negatives for their collection.

The photograph of the region of Theophilus, Cyrillus, and Catharina, near Mare Nectaris (Sea of Nectar), was printed by a screened halftone process, which is less satisfactory than photogravure, and yet it clearly shows finer detail than the photograph of the same region that appeared in the Lick Observatory Atlas. Image source: The Astrophysical Journal. Vol. 12, no. 5, Dec 1900, Chicago: UC Press, 1895, pl. 21.

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