NOVELTY - Solar collector comprises a first concentrator arrangement having a first radiation path with a combustion line portion, which exhibits incident solar radiation (5) alternately in an operating region, and an absorber arrangement for concentrated radiation. The first concentrator arrangement comprises many concentrator sections with a focal line area, and a second concentrator arrangement is provided with many rows of additional concentrators along the length of the absorber arrangement, which are arranged behind one another.    USE - Used as a solar collector.    ADVANTAGE - The solar collector includes trough concentrator, which allows the concentrated radiation to be concentrated in focal point areas with a higher concentration of radiation, thus it achieves higher temperatures in the absorber tube, and improves the efficiency of the power plant.    DETAILED DESCRIPTION - Solar collector comprises a first concentrator arrangement having a first radiation path with a combustion line portion, which exhibits incident solar radiation (5) alternately in an operating region, and an absorber arrangement for concentrated radiation. The first concentrator arrangement comprises many concentrator sections with a focal line area, and a second concentrator arrangement is provided with many rows of additional concentrators along the length of the absorber arrangement, which are arranged behind one another. The additional concentrators of each row respectively exhibit an associated focal line area and are arranged in the first radiation path before the respective focal line area, and the additional concentrators have a second radiation path, each with a focal line area. The collector exhibits a device for running the alignment in an alignment region of additional concentrators against an actual path of a radiation of concentrator section of the first concentrator arrangement. A thermal opening is associated with each row of additional concentrator, respectively along the length of the absorber arrangement, which is arranged on the absorber arrangement in adjacently extending rows. The device is provided for aligning the running additional concentrators, whose focal point areas are fixed in its associated thermal opening. An INDEPENDENT CLAIM is also included for an absorber tube (7), where the absorber arrangement is formed as an absorber tube, and is completely insulated on the outside including the areas situated between the thermal openings.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic representation of the solar collector.    Pressure cell (2)    Flexible membrane (3)    Solar radiation (5)    Absorber tube (7)    Optical element (20)