Solstices

Solstices are those points of the ecliptic which are farthest removed from the equator. When the sun in his apparent path reaches either of these points, he appears stationary; hence the term solstice, from the Latin sol and stare. He then progresses no farther towards the poles, but returns towards the equator. At these two points the sun is vertical at the Tropics of Cancer or Capricorn; hence the solstices are also known as the tropical points. The term solstice is often used to denote the time when the sun reaches the two points. Hence in the northern hemisphere the summer solstice will be June 21, and the winter solstice December 21. The Solstitial Colure is a great circle passing through the solstices, and cuts both the equator and ecliptic at right angles.