An optical imaging system (e.g., hyperspectral imaging system) is described herein which includes imaging optics, an uni-axial homogenizer (including a rectangular cross-section light pipe and an astigmatic paraxial optic), and a detector. The uni-axial homogenizer is configured to preserve imaging along one axis while homogenizing (removing all image information) along a second perpendicular axis. In one embodiment, the uni-axial homogenizer is utilized in a spectrograph of a hyperspectral imaging system where the rectangular cross-section light pipe replaces the entrance slit of the spectrograph and the astigmatic paraxial optic is built into the design of the spectrometer's optics.