Becker Iris Photometer

Year: 195?
Manufacturer: Becker
Materials: aluminum, steel brass, optical glass
Dimensions: L = 60; P = 70; H = 120

Produced in the 1950s, the Becker iris photometer is a variant of the fixed aperture photometer, designed to measure the magnitude of stars on photographic plates. The measurement is made by comparing two light beams: the first passes through the plate with an adjustable aperture via an iris, while the second serves as a reference.

The star’s magnitude was determined based on the iris aperture needed to balance the two beams. This instrument offered greater flexibility compared to the fixed aperture photometer, ensuring precise and reliable measurements.