Johnson and Cousins, UBVRI, Bessell and Sloan SDSS Filters

The filters used today for scientific photometry with digital sensors date back to the Johnson and Cousins filter sets developed in the 1950s-1970s and adapted for CCD cameras by M. Bessell in the 1990s. Today, we have better options available with dielectric filters.

The UBVRI system was developed in the 1950s for the McDonald Observatory 0.9 m telescope and consisted first of a Johnson UBV filter set, later extended by Cousins to include the R and I filters in the red part of the spectrum. The Bessell UBVRI filters are the standard today. The filters of the extended UBVRI system include:

U - Ultraviolet 320-400 nm

B - Blue 400-500 nm

V - Visible 500-700 nm

R - Red 550-800 nm

I - Infrared 700-900 nm