What term describes the great circle that passes through any celestial object and the celestial poles?

The term that describes the great circle passing through any celestial object and the celestial poles is the Hour Circle. This concept is crucial in celestial navigation and astronomy, as it provides a way to locate celestial objects in relation to the Earth. Each celestial object has an hour circle that connects it directly to the north and south celestial poles, analogous to the way lines of longitude operate on Earth.

Hour circles are important in coordinate systems used in astronomy, where the position of a star or planet can be defined by its hour angle. This hour angle is the measure of time since the celestial object last crossed the observer's local meridian, contributing to the understanding of the object's movement and position in the sky over time. Knowing about hour circles allows astronomers and navigators to effectively chart paths across the celestial sphere, facilitating observation and travel.

In contrast, the celestial equator refers to the projection of Earth's equator onto the celestial sphere, while the equatorial plane is a geometric concept defining the plane of the celestial equator itself. The celestial sphere is a model of the sky where stars and celestial objects are projected. While all these terms are related to celestial navigation and the positioning of objects in the sky, the hour circle specifically describes the great circle mentioned in the question