Astrophysics (index)

Strömgren Photometric System

(uvby System, uvby Photometric System)
(four-color photometric system devised in 1950s)

The Strömgren Photometric System is a four-Passband Photometric System devised by astronomer Bengt Strömgren. It is considered a Medium-Band Photometric System, using narrower bands but covering the same general range as the UBV Photometric System, covering Visible Light and some Ultraviolet.


Designator Stands for peak
Full Width At Half Maximum
u "ultraviolet" 350nm 30nm
v "violet" 411nm 19nm
b "blue" 467nm 18nm
y "yellow(?)" 547nm 23nm

Since its development, additions have been devised.