Abstract: A two bulb mercury vapor lamp apparatus includes a housing with a bottom whose cross-section forms a curved "M" shape. A pair of reflectors are attached to the bottom of the housing with each reflector positioned in one-half of the "m". The reflectors direct light from the bulbs onto a focal plane where a photosensitive material is located. A plurality of quartz liquid coolant circulating tubes are positioned between the bulbs and the photosensitive material which tubes both cool the lamp and filter out infrared rays. The coolant tubes are attached to a pair of end blocks which are removably secured to the housing. The end blocks, connected plumbing lines and coolant tubes can be lowered from the housing intact, thus greatly facilitating maintenance access to the bulbs and reflectors.