Concept in Definition ABC

The astrolabe is a very popular element within the field ofAstronomy, since he himself knew how to be, especially in ancient times, a instrument of location during navigation that represented the celestial sphere with its main stars and then it was very useful when observing and determining the height, position and movement of the stars on the horizon. It was also useful to know the time and latitude in which he was.

Instrument used legendarily by scientists and navigators to locate themselves in the sea and to locate stars in the sky

In short and concrete accounts, what the astrolabe allows is to determine the position of the stars, calculate the time, the time, the time of the sun, the rising and setting of the sun, and the location of the moon and the rest of the planets

The term astrolabe has a Greek origin, which precisely coincides with its purpose, since it refers: seeker of stars.

Uses and applications

Mostly, it was used, of course by navigators, but also by astronomers and scientists to be able to locate the stars in space, observe their movements and also to know time and latitude, as we mentioned lines above.

We can also find a close connection with religion, since Muslim navigators used it a lot during their travels to determine the location of Mecca and the time, and thus know what was the precise moment that they should orient themselves to where the astrolabe marked and thus perform the usual prayer.

How does it work?

Technically, the astrolabe is based on a stereographic projection of the celestial sphere, which consists of a circumference graduated or mother plate on whose axis rotates a needle with a crosshair, which, points to the chosen star, while the edge of the mother plate, presents a scale graduated in degrees and in some astrolabs also in hours and minutes. Two discs are inserted in the front of the motherboard, one internal or eardrum (fixed plate that contains engraved the coordinates of the sphere) and another external or spider (has a planisphere transparent with the positions of the sun, the moon and the brightest stars of the place). Above the spider lies the needle that points to the star in question.

The type of stereographic projection proposed by the astrolabe implies a system of representation graph in which the surface of the terrestrial sphere is projected onto a plane through a series of lines that pass through a point. The plane is tangent to the sphere.
The area it represents is larger than that of a hemisphere. In regards to the polar projection, the meridians appear as straight lines, and the parallels as concentric circles.

Astrolabe classes

Various kinds of astrolabe developed, the planispheric ones, which represented the stars. in a single latitude, and the universals who enjoyed the ability to represent all the latitudes.

The apogee of its implementation at the behest of navigation was located between the centuries XVI and XVIII, until in 1750 it was superseded by the creation of the sextant.

Origins and creation

Regarding its creator, there are several controversies, some point to the astronomer and mathematician Claudius Ptolemy like its author, although, such a version is practically discarded when it is known that Hipparchus of Nicaea, before Ptolemy, was already building them and even 5,000 years before these two characters, in the Sumerian culture, the use of the aforementioned astrolabe already existed.

Meanwhile, the oldest astrolabe that to this day is preserved in the National Museum of Kuwait, dates from the year 927 and was built by the astronomer of Persian origin Nastulus.

This navigation instrument of course knew how to be the star for many centuries in terms of location and location of stars, but Of course, the technological development that would ensue over the years made it lose power, precision, compared to other newer proposals, and then it ended remaining in disuse, and so it is that today it is preserved in memory and history but no longer has an active use by navigation or navigation. science.

In terms of location and location in space of various elements, technology has advanced fantastically and modern equipment and devices were developed that make the astrolabe see today as a obsolete invention.

Astrolabe Topics