The Strömgren photometric system is a four-passband photometric system devised by astronomer Bengt Strömgren. It is considered a medium-band photometric system, using somewhat-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"||350 nm||30 nm|
|v||"violet"||411 nm||19 nm|
|b||"blue"||467 nm||18 nm|
|y||"yellow"||547 nm||23 nm|
Since its development, additions have been devised.