Sundial Information

A Sundial is an instrument for measuring time, by means of the location on a plane of the shadow cast by a marker exposed to sunlight. A sundial consists of two parts: a gnomon and a dial plane. The gnomon is the shadow-producing device, usually a metal plate set parallel to the earth’s axis and pointing toward the celestial pole. The dial plane is the flat surface marked with the times of day. A sundial is specially designed for its location on the earth, and tables are used to calculate standard time from solar time, because solar time changes daily with the position of the sun. Sundials were used for judging time before clocks and watches became more available in the 18th century.

A sundial indicates the time by using a protruding marker, called a gnomon, to cast a shadow. The angle of the shadow changes position as the Sun passes from east to west during the course of the day. Markers on the dial are used to measure the angle of the shadow and tell the time (Microsoft Encarta).

This was the primary means of telling time during the Biblical era. In the story of King Hezekiah, the sundial of Ahaz was used as a sign from The Almighty when, upon facing death, the king’s prayers were answered and fifteen years were added unto his life. This was done by the sun going back ten degrees, as it began to set, with the sundial reflecting this movement by its casted shadow:

“Then came the word of the Lord  to Isaiah, saying, Go, and say to Hezekiah, Thus saith the Lord , the God of David thy father, I have heard thy prayer, I have seen thy tears: behold, I will add unto thy days fifteen years. And I will deliver thee and this city out of the hand of the king of Assyria: and I will defend this city. And this shall be a sign unto thee from the Lord , that the Lord  will do this thing that he hath spoken; Behold, I will bring again the shadow of the degrees, which is gone down in the sun dial of Ahaz, ten degrees backward. So the sun returned ten degrees, by which degrees it was gone down” (Isa 38:4-8, KJV)

However, during the night hours, the movement of the constellations and water clocks were used to keep the time, which were in synch with the movements of the sun during the day.​​