Declination

• Declination in Astronomy is the location of a celestial object by its celestial latitude north or south of the Celestial Equator. Its celestial longitude is measured by its Right ascension in degrees travelled from the First Point of Aries, which equates to the Zero Meridian.

Similarity to Latitude and Longitude

• On Earth, a terrestial position is obtained by its Latitude and Longitude.
• In the Sky, a celestial object is also measured by the equivalent of Latitude and Longitude, known as Declination and Right ascension.

• Declination (Latitude)

  • Declination is the Latitude of a celestial object as measured from the Celestial Equator.

• Right ascension (Longitude)

  • The Longitude of a celestial object is called Right ascension, and is measured in Time, by Hours, Minutes and Seconds, from a zero point on the Equator, known as the First Point of Aries. This is where the Sun crosses the Celestial Equator at the Vernal Equinox.
  • Right ascension increases Eastwards, as it is measured in a full circle always moving towards the East.

• Sidereal Hour Angle (SHA)

  • The Sidereal Hour Angle (SHA), is similar to Right ascension, but instead, increases Westwards.
  • It is used in Celestial Navigation