- AU ANUA 224-29
- Item
- nd
Part of ANU Department of Applied Mathematics papers and publications
George W. Ritchey was a a gifted mechanical and optical engineer that played a key role in the early development of Yerkes Observatory of the University of Chicago. He perfected the technique of obtaining high quality photographs with a visually corrected refracting telescope, in this case the famous Yerkes 40-inch refractor, using isochromatic plates and a yellow filter. The method was tested by taking over 65 plates in 1900 and 1901. This set contains two positive and four negative plates with exposures of stars.