5 articles for "Great"

**Great Circle**[Astro*Index]

A circle whose plane passes through the center of a sphere; thus a great circle is the largest circle that can be constructed on the surface of that sphere. It is to be distinguished from a small circle, whose plane does not pass through the center of a sphere. On a sphere, meridians of longitude are great circles.

The following are examples of great circles on the celestial sphere:

• Meridian

• Prime Vertical

• Celestial Equator.

See also:

♦ Small Circle ♦ Meridian ♦ Celestial Sphere ♦ Celestial Equator ♦ Ellipse ♦ Prime Vertical ♦ Ecliptic

**Great Circle**[Munkasey M.]

A circle of the Celestial Sphere which has as itscenter the center of the Celestial Sphere. The Celestial Equator is an example of a Great Circle. See also: "Small Circle".

See also:

♦ Small Circle ♦ Meridian ♦ Celestial Sphere ♦ Celestial Equator ♦ Ellipse ♦ Prime Vertical ♦ Ecliptic

**Great Circle Aspect**[Astro*Index]

*Angular distance* between two bodies, measured along a *great circle* connecting their centers.

See also:

♦ Angular Distance

**Great Pyramid**[Astro*Index]

Located at Giza, Egypt. Geographical coordinates are: E031°13', N30°01'. The ascending passage on the North side pointed to the star Thuban (alpha Draconis) at the time of the pyramid's construction.

See also:

♦ Angular Distance

**Great Year**[Astro*Index]

Time required to complete one full cycle of Precessional Motion of the pole of the Earth's spin-axis about the pole of the Ecliptic: 25,800 years.

See also:

♦ Earth, Motions of ♦ Precession ♦ Ecliptic

Astro*Index Copyright © 1997 Michael Erlewine

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