Abstract: In an evacuated solar collector of the type having an inner absorber member and an outer tubular envelope surrounding the absorber, the space surrounding the absorber being evacuated, the improvement comprising an expansion joint slidably coupling the absorber and the outer tubular member, including first and second sleevable portions being respectively formed to the absorber and the outer tubular member. The sleevable portions are sleeved, one within the other, concentrically forming an angular space therebetween, and a resilient member, disposed in the annular space, slidably supports the absorber member within the outer tubular member in a generally concentric or coaxial manner for allowing the expansion and contraction of the absorber relative to the outer tubular member.