👉 Unsidereal, or sidereal day, is a type of astronomical term that describes the angle of the sun at noon on the surface of Earth. In other words, it refers to the position of the sun in relation to the horizon when the sun is directly overhead, typically around 12:00 noon. In the context of solar systems, sidereal days are important for determining the orientation and location of stars in the night sky. They also help astronomers understand how the Earth's rotation
