Astrolabes were used in astronomy.
An astrolabe is a device that was used in the field of astronomy to check the location of the stars . With the astrolabe, it was possible to indicate the height and position of the stars in the sky.
The etymological origin of the term derives from the Greek astrolabion , which is the result of the sum of two words:
- The noun aster , which is equivalent to "star."
- The name lambion , which is synonymous with "grip" .
Use of the astrolabe
Astronomers and sailors, among others, used astrolabes to find the stars and analyze how they moved: in this way, they could obtain information about time and latitude and even establish distance measurements.
The astrolabe was the most used navigation instrument for several centuries. Technological development, little by little, made it lose preponderance. Today there are much more advanced tools that offer information with greater precision.
It can be said that the astrolabe predominated until approximately 1750 , when the sextant appeared on the scene. And the latter had greater precision, hence it was used not only in the maritime sector but also outside it and in other areas such as the air sector.
An astrolabe shows the location of the stars.
His invention
Although it is true that there is no concrete data that establishes the name of the inventor of the astrolabe, many theories attribute its creation to the Greek mathematician Ptolemy ( 100 – 170 ), a very important figure for his studies and advances in areas such as astrology (to create horoscopes), as well as in geography and optics , among other sectors.
However, it should not be overlooked that other important personalities are considered to have contributed to the development and perfection of the artifact, such as Hypatia of Alexandria and her father, the astronomer Theon .
Types of astrolabe
There were, however, various types of astrolabes. Planispheric astrolabes , for example, could represent the stars at a single latitude. On the other hand, universal astrolabes had the capacity to perform representation in all existing latitudes.
The operation of the astrolabe is based on the celestial sphere : an ideal type sphere that is concentric with the globe and where, apparently, the stars move. The instrument allows you to draw a stereographic projection , which consists of graphically representing the surface of the sphere in a plane.
The astrolabe is made up of a mother plate (a graduated circumference) with a needle that points to the stars . The scale on the edge of the circumference can show degrees and time. In the front sector, two discs are inserted, one with the coordinates that correspond to a latitude and another that rotates and represents the locations of the Moon , the Sun and other stars.