Abstract: In a telescope having primary and secondary reflectors, wherein the actual primary reflector surface deviates from an ideal primary reflector surface, such deviation is compensated for. At least one intermediate element forms an image of the primary surface onto the secondary surface, so each point on the secondary surface corresponds to a point on the primary surface. The secondary surface is formed with a deviation from an ideal secondary surface, with the "piston" distance of each point on the actual secondary surface equal to the piston distance of a corresponding point on the actual primary surface from the ideal primary surface. It is found that this results in electromagnetic (e.g., light) rays which strike a deviating area of the actual primary surface being brought to the same focus as if the actual primary surface did not have a deviation from an ideal primary surface.

Abstract: A single reflective afocal optical module collects and concentrates solar energy onto a receiving surface extending substantially parallel to the focal axis of the optical system and to the central axis of the module. The reflective surface of the collector is shaped to reflect incoming energy and distribute it uniformly over the full surface of the receiver, with the reflective surface preferably consisting of a plurality of discrete reflective surface portions each distributing its portion of reflected energy over the full receiver surface so that the energy portions from the respective reflective surface portions are superimposed on one another on the receiver. The reflector and receiver are housed in a sealed enclosure having a transparent window for admitting incoming energy, and heat extracting means removes excess heat from the enclosure.

Abstract: Modular structures for the collection, concentration and conversion of solar energy to another usable form such as electrical energy. The structures feature three conic section reflective surfaces, two of which focus in front of a receiver element and off the axis of the structure. The third reflective surface is utilized to redirect that energy which would otherwise miss the receiver element to improve overall efficiency.