For this week I want to talk about the Armillary Sphere, in Antiquus we have the models, small and large (Below photos)
The Armory Sphere is an old instrument used until the year 1600 that was used to determine the celestial coordinates of the stars (celestial coordinates are the set of values that, according to a given reference system, give the position of an object in the celestial sphere There are several celestial coordinates according to their origin and reference plane: a first classification divides them into two large groups, depending on whether they are Cartesian Coordinates or Spherical Coordinates)
In Latin, armilla means ring, ring or bracelet. From there arose the name of the armillary sphere, used to designate a model or representation in three dimensions of the sphere. The didactic work with the armillary sphere is a good complement to that described by the equator, the tropics, the celestial polar circles and the ecliptic. . The gadget consists of a set of concentric rings arranged around a small sphere that serves as the Earth
It is believed that it was invented around 255 BC. by the Greek astronomer Eratosthenes of Cyrene (276-195 a.C.), Greek astronomer, mathematician and geographer who lived mainly in Alexandria, whose famous library he directed.
In ancient Greece, as in China, where for some it appeared for the first time, or in Persia, the armillary sphere served to make observations and calculations of certain astronomical magnitudes, including the angle of the Equator with the Ecliptic.
As a scientific instrument, the Arabs also used it, and from Andalusia they introduced it to Western Europe, where the Danish astronomer Tycho Brahe (1546-1601) was one of those who made extensive use of it (The armillary sphere that Antiquus reproduces is the replica of one of those manufactured by said astronomer). In fact, until the invention of the optical telescope in the seventeenth century was the astronomical instrument par excellence.
It was built by a certain number of circles (from which comes its Latin name "armilla", which means bracelet) inserted into each other, representing the celestial equator, the ecliptic, the horizon, the zodiac, etc., in such a way that once directed towards a star, its celestial coordinates could be read on graduated scales. It is manufactured entirely in wood and brass and is accompanied by a manual with its history and instructions for use.
With the purchase of this product we send free a set of our five astronomical postcards: astrolabe, nocturla, sundial, lunar and tidal calendar and, finally, perpetual calendar. valued at € 25
I leave this explanatory video:
Sources: Science in the classroom