Prof. F. A. Lindemann's prototype Photoelectric Stellar Photometer made at the Claredon Laboratory, Oxford in 1919. Prof. F. A. Lindemann's prototype Photoelectric Stellar Photometer made at the Claredon Laboratory 1919
Salford Electrical Instruments exposure photometer with supplementary lens attachment and manual, 1950-1959. Salford Electrical Instruments exposure photometer with supplementary lens attachment and manual