The Astrolabe
from Astrolabes.org


A Mariner's Astrolabe, designed for navigation.

The astrolabe is a very ancient astronomical computer for solving problems relating to time and the position of the Sun and stars in the sky.

Astrolabes are used to show how the sky looks at a specific place at a given time. This is done by drawing the sky on the face of the astrolabe and marking it so positions in the sky are easy to find. To use an astrolabe, you adjust the moveable components to a specific date and time. Once set, the entire sky, both visible and invisible, is represented on the face of the instrument. This allows a great many astronomical problems to be solved in a very visual way. Typical uses of the astrolabe include finding the time during the day or night, finding the time of a celestial event such as sunrise or sunset and as a handy reference of celestial positions.

posted by awiggins | 02:23 PM