from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A medieval instrument, now replaced by the sextant, that was once used to determine the altitude of the sun or other celestial bodies.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. An astronomical and navigational instrument for gauging the altitude of the Sun and stars.
from the GNU version of the Collaborative International Dictionary of English
- n. An instrument for observing or showing the positions of the stars. It is now disused.
- n. A stereographic projection of the sphere on the plane of a great circle, as the equator, or a meridian; a planisphere.
from The Century Dictionary and Cyclopedia
- n. An obsolete astronomical instrument of different forms, used for taking the altitude of the sun or stars, and for the solution of other problems in astronomy.
- n. A stereographic projection of the sphere, either upon the plane of the equator, the eye being supposed to be in the pole of the world, or upon the plane of the meridian, the eye being in the point of intersection of the equinoctial and the horizon.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. an early form of sextant
The other instrument, called the astrolabe, was a brass circle marked off into 360 degrees.
In the latter there is one of the oldest examples of the figures then found almost invariably on the reverse of the so-called astrolabe, a graduated quadrant with the help of which one could obtain the different hours of the day from the observation of the sun's height.
They set out to find a second youth -- the dream of immortality -- with the astrolabe, which is the creed or Koran all take as their guide.
The astrolabe was a highly developed tool used throughout the Muslim world to measure the altitude of stars and planets.
The problem of fixing geographical location was resolved with the use of the "astrolabe", which made it possible to measure the angle of the sun and that of the pole star.
He visited Portugal about 1480, invented a new kind of astrolabe, and sailed with it in 1484 as cosmographer in Diego Cam's voyage to the Congo.
This sketch would be incomplete without some reference to the mysterious astrolabe which is alleged to have been found in the month of August,
The '' 'astrolabe' '' was a compact round disc used to observe and calculate the position of [[celestial bodies]] before the invention of the [[sextant]].
The '' 'astrolabe' '' was a compact round disc used to observe and calculate the position of
They enabled Muslim astronomers to create the first accurate maps of the heavens, and then to create an astonishingly sophisticated version of the astrolabe, a handheld navigation device.