This star finder, designed for aeronautical use, was based on the Rude form as modified by Elmer Collins of the United States Hydrographic Office. It consists of a white plastic planisphere with the northern sky on one side and the southern on the other that shows all the stars in the American and the British Air Almanacs; nine clear plastic altitude-azimuth templates for use at different latitudes up to 85o north and south; an instruction card; and a leatherette container. It was published in March 1942 under the authority of the Secretary of the Navy, and cost $2.50. The Hydrographic Office transferred this example to the Smithsonian in 1957.
Ref: E. B. Collins, "Star Finder," U.S. patent #2,304,797
E. B. Collins, "Star Finder," U.S. patent #2,337,545
Nathaniel Bowditch, American Practical Navigator (Washington, D.C.: Unted States Hydrographic Office, 1943), pp. 212-214.
"Elmer B. Collins," Washington Post (2 October 1958), p. B2.>