between the trough end plates 22 and the heat exchanger tube 31 the reflective trough cover lens 24 is made of suitable clear plastic or other clear material and is sealed into the preformed channels 19 fig2 of the trough 21 and end plates 22 by a silicone rubber sealant 26 and provides both rigidity and weatherproofing of the collector assembly the sealant may be similar to dow corning dc 4 or other suitable high temperature sealant cover lens spacers 25 are bonded to cover lens 24 along the center line axis at suitable intervals to provide proper spacing between the cover lens 24 and the absorber assembly 30 installation of absorber assembly 30 precedes final assembly and sealing of trough cover lens 24 and end plates 22 the solar absorber assembly 30 is comprised of a metal heat exchange tube 31 preferably copper or aluminum of suitable size in thermal contact with the absorber plate 33 by means of a heat conducting silicone lubricant 32 the lubricant 32 provides for both heat transfer and rotational movement between the absorber plate 33 and the heat exchange tube 31 the absorber plate 33 is formed of suitable thin gauge metal by conventional roll forming methods or sheet metal tooling or extrusion molded utilizing high temperature black plastic or other suitable material through a die shaped to the absorber plate.