What is the triangle formed by the north celestial pole, zenith, and the sun or star called?

The triangle formed by the north celestial pole, the zenith, and the sun or a star is referred to as the Astronomical Triangle. This term is significant in celestial navigation and astronomy because it describes the relationships and geometrical relationships among celestial bodies and observer locations. Such triangles are essential for determining positions and making accurate calculations regarding celestial movements.

The use of the north celestial pole in this context highlights the role of pole stars in navigation and timekeeping, while the zenith indicates the point directly above an observer. This geometrical formation allows navigators to measure angles between these key points, ultimately leading to better understanding and determination of one's position on Earth relative to celestial objects. This triangle is a foundational concept in celestial mechanics, vital for those studying surveying and navigation.