What is meridian astronomy?

Meridian astronomy is a branch of astronomy that deals with the study of celestial objects and events that take place near or along the celestial meridian. The meridian is an imaginary line on the celestial sphere that runs from the North celestial pole to the South celestial pole and passes through the zenith of the observer's location.

In meridian astronomy, astronomers typically use instruments such as transit telescopes and meridian circles to observe and measure the positions of celestial objects as they cross the meridian. The transit telescope is a specialized telescope that is mounted on a fixed axis and pointed at the celestial meridian. It is used to observe the passage of celestial objects across the meridian and to determine the exact moment when they cross the meridian.

Meridian circles are instruments designed to measure the positions of celestial objects accurately along the meridian. They consist of a telescope mounted on a vertical axis that is aligned with the meridian. The telescope is equipped with a system of mirrors and prisms that reflect the image of the celestial object being observed onto a scale below the telescope. The scale is marked with graduations that allow the observer to measure the precise position of the object.

Meridian astronomy is used in various fields of astronomy, including astrometry, navigation, and timekeeping. The precise measurements of celestial positions provided by meridian astronomy are essential for understanding the movements and dynamics of celestial objects and for accurate navigation and timekeeping.