Astrophysics (index)

UBV Photometric System

(Johnson System, Johnson-Morgan System)
(commonly-cited photometric system for describing stars' colors)

The UBV Photometric System, also called the Johnson System or Johnson-Morgan System, is an early well-accepted Photometric System and is the system to be assumed if no other system is specified or implied.

It specifies U, B, and V Bands, in turn, specifying specific B-V and U-B color indices. Magnitudes are calibrated as zero for A0 V Stars unaffected by Reddening.

The UBVRI Photometric System, i.e., Johnson-Cousins System is an extension with red and Infrared passbands, R Band and I Band.

The UBVI Photometric System uses the B, V, R, and I from the UBVRI system, but typically with a narrower U band from a system by Thuan and Gunn.


Referenced by:
Color Index
I Band
Photometric System
Strömgren Photometric System
Vega System