Declination

Declination (abbrev. dec or δ) is a word used in astronomy to describe one of the two coordinates of the equatorial coordinate system, the other being either right ascension or hour angle. Dec is comparable to latitude, projected onto the celestial sphere, and is measured in degrees north and south of the celestial equator.

Declination Media

• 

  Right ascension and declination as seen on the inside of the celestial sphere. The primary direction of the system is the vernal equinox, the ascending node of the ecliptic (red) on the celestial equator (blue). Declination is measured northward or southward from the celestial equator, along the hour circle passing through the point in question.

• 

  Right ascension (blue) and declination (green) as seen from outside the celestial sphere.

• 

  The night sky, divided into two halves. Declination (blue) begins at the equator (green) and is positive northward (towards the top), negative southward (towards the bottom). The lines of right ascension (blue) divide the sky into great circles, here 1 hour apart.