Definition
The term is loosely used to refer to any clock that shows, in addition to the time of day, astronomical information. This could include the location of the sun and moon in the sky, the age and phase of the moon, the position of the sun on the ecliptic and the current zodiac sign, the sidereal time, and other astronomical data such as the moon's nodes (for indicating eclipses) or a rotating star map. The term should not be confused with astronomical regulator, a high precision but otherwise ordinary pendulum clock used in observatories.
Astronomical clocks usually represent the solar system using the geocentric model. The center of the dial is often marked with a disc or sphere representing the earth, located at the center of the solar system. The sun is often represented by a golden sphere (as it initially appeared in the Antikythera Mechanism, back in the 2nd century BC), shown rotating around the earth once a day around a 24 hour analog dial. This view accords both with daily experience and with the philosophical world view of pre-Copernican Europe.
Read more about this topic: Astronomical Clock
Famous quotes containing the word definition:
“The physicians say, they are not materialists; but they are:MSpirit is matter reduced to an extreme thinness: O so thin!—But the definition of spiritual should be, that which is its own evidence. What notions do they attach to love! what to religion! One would not willingly pronounce these words in their hearing, and give them the occasion to profane them.”
—Ralph Waldo Emerson (1803–1882)
“It’s a rare parent who can see his or her child clearly and objectively. At a school board meeting I attended . . . the only definition of a gifted child on which everyone in the audience could agree was “mine.””
—Jane Adams (20th century)
“Was man made stupid to see his own stupidity?
Is God by definition indifferent, beyond us all?
Is the eternal truth man’s fighting soul
Wherein the Beast ravens in its own avidity?”
—Richard Eberhart (b. 1904)