Optical observations refer to the use of visible light, typically in the range of 400-700 nanometers, to study objects and phenomena in space. This includes the observation of stars, planets, galaxies, and other celestial bodies using telescopes and other optical instruments. Optical observations provide valuable information about the composition, structure, and behavior of objects in the universe, helping scientists to better understand the workings of the cosmos. By studying the light emitted or reflected by these objects, researchers can learn about their temperature, mass, velocity, and many other important characteristics. Optical observations are a foundational tool in astronomy and astrophysics, providing key insights into the nature of the universe.