A Lyot filter is an optical device used primarily in astronomy and spectroscopy to isolate specific wavelengths of light. It consists of multiple optical elements, including polarizers and birefringent crystals, which work together to selectively transmit light while blocking other wavelengths. This allows scientists to study particular spectral lines in detail. The filter is named after the French physicist Bernard Lyot, who developed it in the 1930s. Lyot filters are particularly useful in solar observations, enabling researchers to analyze the Sun's atmosphere and magnetic fields by filtering out unwanted light and focusing on specific emissions.