MOBY was designed with three internal reference lamps; a red light emitting diode (LED), a blue LED and an incandescent lamp. The purpose of the internal reference lamps is to monitor the stability of MOBY measurements during the three month deployments. Internal reference lamp measurements from the first day's data are used as a reference for the remainder of the deployment. Ratio's of internal reference data with reference data show changes in the MOBY system and lamps during the deployment. These variations include changes in current supply to the lamps, changes in spectrograph sensitivity, temperature variations, and degradation of the lamps radiant flux over time.