August Herman Pfund (December 28, 1879 – January 4, 1949) was an American physicist, spectroscopist, and inventor.
Both Wood and Pfund left Wisconsin for Johns Hopkins University in 1903.
He remained at Hopkins for the remainder of his career, eventually becoming a full professor and later chair of the physics department.
He also invented the Pfund telescope, which is a method for achieving a fixed telescope focal point regardless of where the telescope line of sight is positioned, and the Pfund sky compass,[1] which arose from Pfund's studies of the polarization of scattered light from the sky in 1944, and which greatly helped transpolar flights by allowing the determination of the Sun's direction in twilight.
[2] Pfund is also noted for his work into the area of infrared gas analysis.