An imaging spectrometer (100) is provided, comprising: an entrance opening (101) configured to admit light to the spectrometer (100), a coded aperture (120), at least one dispersive element (111, 112), a two-dimensional array detector (130), and a plurality of converging optical elements (121, 122, 123, 124). The plurality of converging optical elements (121, 122, 123, 124) are configured to focus light from the entrance opening (101) at the coded aperture (120), and to focus light from the coded aperture (120) at the detector (130). The coded aperture (120) is arranged to modulate light from the entrance opening (101) in at least one of the spatial and spectral domain. The at least one dispersive element (111, 112) comprises a dispersive element (111, 112) between the coded aperture (120) and the detector (130). The at least one converging optical element (121, 122, 123, 124) comprises at least one concave reflector.