- circles used in a horizontal plane, north and south of the equator, that along with longitude, establish a system for locating positions on the earth.

- values of latitude are measured in degrees and range from 0 degrees at the equator to 90 degrees north or south of the equator at the north and south poles respectively.

Longitude

- circles in a vertical plane that along with latitude, establish a system for locating positions on the earth.

- values of longitude are measured in degrees and establish positions east or west relative to the 0 degree longitude line.

- the 180 degree longitude line is also known as the International Date Line.
 

Along with this system for establishing positions on earth, there is a celestial coordinate system which allows positions of stars to be located.

Declination

- these lines are direct extensions of the circles of latitude on the earth; a measurement of the angular distance of a star north or south of the celestial equator.

- values of declination are measured in degrees and range from 0 degrees at the celestial equator to 90 degrees at the north celestial pole.

Right Ascension

- these lines correspond to longitude; a measure of a star's position east or west of a position on the celestial sphere called the vernal equinox.

- values of right ascension are measured in hours, minutes, and seconds; 24 hours = 360 degrees so 15 degrees = 1 hour.

Back to The Stars: A Start to the Sea

WaveCrest - developed be Tina Huss, Alenne Grabowski, Mike Pable, & Francis M. Redmon

This page submitted by St. Norbert College Ocean Voyagers Program