A spectroscope is a device which measures the spectrum of light. Early spectroscopes were simply a prism with graduations marking wavelengths. Modern spectroscopes generally use a diffraction grating, a movable slit and some kind of photodetector[?], all automated and controlled by a computer.
... are many tatpurushas (one for each of the nominal cases, and a few others besides); in a tatpurusha, one component is related to another. For example, a doghouse ...