Johnson photometric system

The Johnson photometric system is a method used in astronomy to measure the brightness of stars and other celestial objects. Developed by astronomer Harold Johnson in the 1960s, it uses specific filters that isolate light in certain colors, typically blue (B) and yellow-green (V). By comparing how bright an object appears through these filters, astronomers can determine its color and temperature, which helps classify stars and understand their characteristics. This system allows for consistent measurements across different studies and contributes to our knowledge of the universe.