A linear focusing solar concentrator is described that uses two reflecting troughs, one is a large, stationary hemi-cylinder and the other is small and tracks the sun. The small reflector weighs less than a parabolic trough with the same concentrator aperture therefore diurnal steering is more feasible. Energy is carried to the job by solar heated fluid in a pipe at focus in the secondary reflector assembly. Theory is presented and comparisons are given for east-west and north-south oriented parabolic and two-trough collectors. In the ideal world, the parabolic outperforms the two-trough collector however in the real world, the simplifications due to the immobile, hemi-cylinder, large reflector may outweigh its disadvantages.