The Astrolabe : the first astronomical computer.

[marwen]

:salambox:
What is the Astrolabe ? :><:

The Astrolabe is an astronomical device which apeared many centuries before Islam (mainly used in ancient Greece) but it was highly developed in Islamic world by 800 and was introduced to Europe from Islamic Spain (Andalusia) in the early 12th century.

Astrolabe:

Components:

It was the most popular astronomical instrument until about 1650, when it was replaced by more specialized and accurate instruments. Astrolabes are still appreciated for their unique capabilities and their value for astronomy education.

But What is it , and How does it work ?

In its earlier form it consisted of a disk of wood suspended by a ring.
Around the disk edge were marked the degrees of the circle; a pointer
along which the sun or another star could be sighted was pivoted on a
centre pin.
Later on the astrolabes were often made of metal with a plate with the
map of the stars and the zodiac circle on the reverse side. It was then
possible determine the time of the day: after measuring the sun´s altitude,
its position was noted on the circle of the zodiac, a line drawn to a circle
of hours showed the time. ( From Encyclopaedia Britannica)
source..

A nice explanation of How is an Astrolabe used in this video..

more informations on the history of Astrolabe..