How do right ascension and declination help astronomers point a telescope?

Astronomers use right ascension and declination as a coordinate system to pinpoint the location of celestial objects on the celestial sphere. This system is directly analogous to terrestrial latitude and longitude, providing a reliable map for aiming a telescope.12

• Right Ascension ($\alpha$): This is the east–west coordinate, measured eastward from the vernal equinox along the celestial equator. It is typically expressed in units of time (24 hours) rather than degrees, reflecting the rotation of the sky.32
• Declination ($\delta$): This represents the angular distance of an object north or south of the celestial equator. North is positive and south is negative, with the celestial poles at +90° and -90° respectively.4

By setting a telescope to these specific coordinates, astronomers can accurately locate stars, planets, and other bodies. Because of the Earth's precessional motion, these coordinates are specified for a particular year to ensure precision.2