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. Read more about astrolabes here. http://www.astrolabes.org/ This is the most beautiful scientific instrument I have ever seen and I want one! via