A spectrometer is a measuring device that collects light waves. It uses these light waves to determine the material that emitted the energy, or to create a frequency spectrum. Astronomers make the most frequent use of spectrometers to determine the makeup of stars or other celestial. Spectrophotometry is a technique used to measure how much light a substance absorbs at different wavelengths. By analyzing how much light is absorbed at specific wavelengths, we can learn. An optical spectrometer, like the Ossila USB spectrometer, is the most common type. It helps identify the composition, structure, and properties of substances by analyzing how they absorb, emit, or scatter light.