The armillary sphere exhibits a series of rings that shape a celestial globe. These circles form its skeleton with the different coordinate grids (equator, ecliptic, meridian, and their parallels) to model the motions in the sky. Effectively, it is a mixture between a celestial globe and a 3D-astrolabe. The armillary sphere is based on the geocentric view: the virtual observer namely the Earth is placed at its centre. An outside horizontal ring represents the horizon. The touching points of the ecliptic and the equator rings are the spring and autumn equinox, respectively. When replacing the Earth by the sun, it can also serve as a Copernican system.

ca. AD 400: The astrolabe is an astronomical instrument used for manifold applications. These include measurements of angles (e.g. culmination heights of stars), positions of celestial bodies, determination of time at a given latitude and vice-versa, and triangulation. Thus, it has been an essential tool for localisation during expeditions and for navigation. As a predecessor of the modern planisphere, it demonstrates the daily and annual motion of the sky. The astrolabe is made up of a main disk of brass and one or more hollow plates which are pivoted against each other. The main disk is engraved with lines that form important coordinate grids. The hollow plate is constructed for a specific latitude and shows the portion of the celestial sphere which is above the local horizon at a given time. Some astrolabes have a narrow rule or label which rotates over the upper disk. It is marked with a scale of declinations. The backside has another rule (Alhidade) in addition, which provides a bearing device to measure angles.

ca. AD 150: Ptolemy (ca. AD 90-160) was the author of several scientific treatises. The most important one is the Almagest ("The Great Treatise"), consisting of 13 books. There he had gathered the astronomical knowledge of his predecessors scattered throughout 800 years. The books VII and VIII contain a star catalogue of 1022 stars, which is an appropriated and supplemented version of Hipparchus' list. Ptolemy's astronomical models were accompanied by convenient tables, which could be used to compute the future or past positions of the planets. He also described the construction of a celestial globe (Book V, Ch. I). It consisted of a graduated circle inside which another could slide. As much as we know, Ptolemy built at least one by himself.

ca. 134 BC: The star catalogue appears close to the development of the graphical depiction of the sky. It is a list or tabulation of stars referred to simply by numbers. Timocharis (ca. 320-260 BC) and Aristillus (ca. 280 BC), both of Alexandria, are said to have created the first catalogue of the Western world. Over 150 years later, the Greek astronomer and mathematician Hipparchus of Nicaea (ca. 190-120 BC) would compile his own one. By comparison to Timocharis' catalogue, he discovered the precession of the equinoxes. Hipparchus' interest for the catalogue may have been inspired by the observation of a new bright star (supernova) that he did not notice before. He decided to plot a map and recorded 850 stars with entries of latitude and longitude relative to the ecliptic. The catalogue was lost during the Middle Ages, but his work was incorporated in the Almagest by Ptolemy. Of the 14 books by Hipparchus, the only survived work is a critical commentary on Aratus' Phaenomena which gives us an indirect link to Eudoxos.