Year 1000
The astrolabe is an instrument used to determine the time of sunrise and sunset very quickly. It is much faster than the mathematical calculations that would be necessary to find the same information. The astrolabe uses technology that was first thought of more than two thousand years ago. The first astrolabes were made in the 4th century. In the 11th century Arab writers describe changes made to the basic astrolabe which increased the usefulness of the instrument. They describe how by switching the measuring plates, the astrolabe could make measurements at different locations or latitudes.