Aspects and embodiments are generally directed to modular imaging spectrometer assemblies and methods of operation thereof. In one example, a modular imaging spectrometer assembly includes foreoptics to receive electromagnetic radiation and produce a real exit pupil, the foreoptics having a first f-number, a first imaging spectrometer to receive and disperse the electromagnetic radiation into a first plurality of spectral bands at a first image plane, the first imaging spectrometer having a second f-number independent of the first f-number, a second imaging spectrometer separated from the first imaging spectrometer, the second imaging spectrometer to receive and disperse the electromagnetic radiation into a second plurality of spectral bands, the second imaging spectrometer having a third f-number independent of the first f-number, and at least one slit aperture positioned to receive the electromagnetic radiation from the real exit pupil and direct the electromagnetic radiation to the first and second imaging spectrometers.