The Octant

Octans Constellation

Origin of the Constellation

Octans is another one of the constellations invented by by Abbe Nicholas Louis de Lacaille who mapped the stars of the southern hemisphere from the Cape of Good Hope in the years from 1751 to 1753.

Octans is named after the octant invented by the Englishman John Hadley around 1730. So it has sometimes been known as Octans Hadleianus. The octant is a navigational instrument incorporating a telescope. It is the predecessor of the modern sextant. The octant has its name because the instrument spanned an angular range of 45°, that is, one eighth of a circle. The modern sextant spans the larger angular range of 60°, one sixth of a circle.

Octans is notable only for containing the South Celestial Pole. There is no bright star near the Pole, and no star in Octans at all brighter than fourth magnitude.  


Copyright © 1998 - 2010 by Arnold V. Lesikar,
Professor Emeritus
Dept. of Physics, Astronomy, and Engineering Science,
St. Cloud State University,St. Cloud, MN 56301-4498

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