1. A method of generating a reconstructed optical spectrum from light radiated from a source and incident on a static multimode multiplex spectrometer, the method comprising: determining a correction mask that compensates for a non-ideal response of a propagation kernel of an optical system in the spectrometer; producing a dispersed mask image at a detector array of the spectrometer by applying the propagation kernel to the incident light; and electronically processing the dispersed mask image based on the correction mask to generate the reconstructed optical spectrum with reduced spectral artifacts.