Declination
The Declination is the angular distance (in degrees)measured north or south from the Celestial Equator, as seen in the Celestial Sphere. It is the equivalent of the latitude in an Earth's geographical map.
When looking at the Celestial Sphere, declination 0° is any position on the Celestial Equator, declination +90° is the North Celestial Pole and declination -90° is the South Celestial Pole. Regarding the position of the stars, it changes slowly with time. Currently the declination of the star Polaris is +89° 15′ 50.8″, very close to the North Celestial Pole, reason for which it is known as the North Star. This position will change with the Earth's movement of precession, as we will see in a future post.
Previous Posts
Concepts in Astronomy #1. Introduction
Concepts in Astronomy #2. The Ecliptic
Concepts in Astronomy #3. The Celestial Equator
Concepts in Astronomy #4. Right Ascension