The UBV photometric system (Ultraviolet, Blue, Visual), also called the Johnson system (or Johnson-Morgan system), is a wide band photometric system for classifying stars according to their colors.
UBV systém alebo Johnsonov systém alebo aj Johnsonov-Morganov systém je širokopásmový fotometrický systém na klasifikáciu hviezd podľa ich farby.