What is an astrolabe?

An astrolabe is an ancient astronomical instrument, where is represented the celestial sphere through an illustration, in order to be able to measure both the movement and the position of the stars. It is an instrument of circular shape, whose constituencies are divided into grades, which are displayed using an arm mobile, similar to the arms of a clock.

The name of this particular instrument comes from the union of two Greek words, "Astro" and "Lip". The first one is translated into the Spanish as "Star", while the term "lip" is understood as "he who seeks". Thus, having an astrolabe we are faced with a "Star seeker"

To be able to measure the height in the sky which are, celestial bodies is necessary that point zero circle with the horizon, in this way, what indicates the mobile arm may be interpreted as the "height" in the sky that it was intended to meet.

As already mentioned, it is a very ancient instrument, in fact who first ventured to use it was the Greek Hipparchus of Nicaea, who around the year 150 BC, was able to design the first issue through the use of the theory of the stereographic projection. These basic navigation instruments were used until the 18th century when they were able to be replaced with sextants. However, a few centuries before, specifically in the 16th century, the Danish astronomer Tycho Brahe was able to build an astrolabe's three meter RADIUS that could make so important and precise measurements, which gave rise to the formulation of theories, still in force, of the Solar System.

From the use of the astrolabe measurements around the celestial bodies can be not only performed, but that you can also do much more simple operations, and calculate the time of the day or night or determine the start time of the stars.
Translated for educational purposes.
Meanings, definitions, concepts of daily use