Abstract: A portable flash tube intensity monitoring system which includes: an internal power supply; a human eye spectral response photodiode for producing analog signals, each of which is directly proportional to the intensity of each flash from the flash tube; electronics for converting each of the analog signals to a digital time function proportional to the intensity of the corresponding flash; electronics, including a microprocessor, for monitoring the digital time function, for flagging a time function which is below a preselected minimum, for communicating status signals to a localized operator display when the time function is below the preselected minimum, and for testing of an internal power source; a fixed distance indicator which allows accurate measurement from a remote coordinate location; and an operator display. The monitoring system is preferably integrally formed for ease of use and portability.