The Cyclops Model 878 is a spherical blackbody source. It consists of an inner black sphere that sits inside a spherical furnace and is suitable for use as a radiation source for infrared thermometers.
The inner sphere has a nominal diameter 230mm is accessed by an optical sighting tube. The furnace can be supplied in one of two constructions, one providing an aperture size of 17mm and one of 45 mm.
The furnace can be adapted for thermocouple operation by replacing the inner sphere with an equalizing block and using a different control sensor.