Lumen 200 Series fluorescence systems specifically illuminate fluorescently labeled specimens using a 200 Watt metal arc lamp with a 2000 hour life span. The light is coupled to the microscope via a two or optional three meter liquid light guide that ensures even illumination and eliminates the need for complex bulb alignment. The lamphouse is removed from physical contact with the microscope, which eliminates heat transfer and provides thermal stability for long term experiments. DC power supply eliminates light flicker. Two models are offered, the standard Lumen 200 and the Lumen 200Pro, which adds a six position, 25 mm diameter high speed filter wheel and high speed variable aperture shutter for attenuation or shuttering of the light source.