Spectroscopy

![A huge diffraction grating at the heart of the ultra-precise ESPRESSO spectrograph.[3]](/uploads/202501/13/A_Taste_of_ESPRESSO5932.jpg)
![UVES is a high-resolution spectrograph on the Very Large Telescope.[11]](/uploads/202501/13/UVES_on_UT2-KUEYEN5932.jpg)
Spectroscopy /spɛkˈtrɒskəpi/ is the study of the interaction between matter and electromagnetic radiation. Historically, spectroscopy originated through the study of visible light dispersed according to its wavelength, by a prism. Later the concept was expanded greatly to include any interaction with radiative energy as a function of its wavelength or frequency. Spectroscopic data is often represented by a spectrum, a plot of the response of interest as a function of wavelength or frequency.