Celestial Object Facts



  • Looking at the stars, they seem to move across the night sky as though they were painted on the inside of a giant, slowly turning ball. This is the celestial sphere.
  • The northern tip of the celestial sphere is called the North Celestial Pole.
  • The southern tip is the South Celestial Pole.
  • The celestial sphere rotates on an axis which runs between its two celestial poles.
  • There is an equator around the middle of the celestial sphere, just like Earth’s.
  • Stars are positioned on the celestial sphere by their declination and their right ascension.
  • Declination is like latitude. It is measured in degrees and shows a star’s position between pole and equator.
  • Right ascension is like longitude. It is measured in hours, minutes and seconds, and shows how far a star is from a marker called the First Point of Aries.
  • The Pole Star, Polaris, lies very near the North Celestial Pole.
  • The zenith is the point on the sphere directly above your head as you look at the night sky.