Saturday, July 19, 2008

Took these shots in Hilton Head...

Neptune: (Latin: Neptūnus) is the god of water and sea in Roman mythology, a brother of Jupiter and Pluto.

Sundial: an instrument to show the time of day by the shadow of a gnomon (The 'shadow-maker' of the sundial is called a gnomon)on a usually horizontal plate or on a cylindrical surface.

One of the first applications of astronomy in the ancient world was keeping track of time and the seasons. For agricultural societies, knowing when to plant and reap crops was extremely important; in addition, you will notice that many holidays are celebrated near or on days of astronomical events (e.g., the winter solstice or the first moon after the spring equinox).

The first time used was Apparent Time, which is based on the position of the sun (i.e., where the sun appears in the sky). This is the time that you would read on a sundial. The basic defining characteristic of Apparent Time is noon, which occurs when the sun is on the meridian.

A meridian (or line of longitude) is an imaginary arc on the Earth's surface from the North Pole to the South Pole that connects all locations running along it with a given longitude. The position of a point on the meridian is given by the latitude. Each meridian is perpendicular to all circles of latitude at the intersection points. Each is also the same size, being half of a great circle on the Earth's surface and therefore measuring 20,003.93 km.

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