Abstract: A sun tracking solar energy collector assembly having both a longitudinally extending flat plate absorber and a tube absorber spaced from and extending longitudinally generally parallel to the flat plate absorber. In one form a parabolic reflector focuses direct rays of solar radiation on the tube absorber and directs diffused rays of solar radiation onto the plate absorber. In another form a Fresnel lens plate focuses direct rays of solar radiation on the tube absorber and flat reflector surfaces direct diffused solar radiation passing through the lens plate onto the plate absorber. In both forms a fluid is first heated as it circulates through passages in the flat plate absorber and then is further heated to a higher temperature as it passes through the tube absorber.