Abstract: An improved illumination system has a lamp encased in a translucent tube with open ends coupled to endcaps via seals disposed circumferentially around the open ends and securing the tube to the endcaps in removable engagement. The seals are compressed between the tube and a securing nut or collar, forming a watertight seal. The endcaps include electrical connectors for providing electrical power to the encased lamp, coupled to electrical circuitry such as a ballast transformer encased in a sealed housing, via conductors in sealed conduits leading to the endcaps. The illumination system can have two or more lamps in respective transparent tubes, in parallel relation with support tubes and conduits leading from the circuitry to the endcaps. Preferably, end portions of the conduits and tubes are angled, for example at 45 degrees with respect to a center portion, for positioning the transparent tubes at a plane displaced from that of the housing.