The armillary sphere was reintroduced in the national arms and in the national Flag of Portugal in 1911. Armillary spheres were among the first complex mechanical devices. Their development led to many improvements in techniques and design of all mechanical devices. Renaissance scientists and public figures often had their portraits painted showing them with one hand on an armillary sphere, which represented the zenith of wisdom and knowledge. Each of the signs of the zodiac is engraved upon the ecliptic ring which is also calibrated with a calendar scale enabling the instrument to be used to model the apparent motion of the sun and the stars at any time of the year. The instrument could be used not only to model the movements and relative geometry of the heavens, but to carry out all sorts of calculations such as the times of sunrise and sunset, the length of a day, and the altitude of the sun or stars. There is no evidence for the Hellenistic origin of the spherical astrolabe, but rather evidence so far available suggests that it may have been an early but distinctly Islamic development with no Greek antecedents."

This particular instrument is Italian, made in Rome in 1588, and is signed by Carlo Plato. It has a number of unusual features that make it rather special, such as the moon mounted on a separate ring within the sphere, and a number of stars represented by individual pointers. Great Circle: a largest circle along the surface of a sphere, whose center coincides with the center of the sphere. In Renaissance Europe, the armillary sphere was amongst the first complex mechanical devices. Public figures often had their portraits painted showing them with one hand on an armillary sphere which represented the height of wisdom and knowledge.a b c d Editors of Encyclopædia Britannica. (16 November 2006). " Armillary Sphere." Encyclopædia Britannica. Accessed 14 October 2017. The flag of Portugal features an armillary sphere. The armillary sphere is also featured in Portuguese heraldry, associated with the Portuguese discoveries during the Age of Exploration. Manuel I of Portugal, for example, took it as one of his symbols where it appeared on his standard, and on early Chinese export ceramics made for the Portuguese court. In the flag of the Empire of Brazil, the armillary sphere is also featured.

Williams, Henry Smith (2004). A History Of Science. Whitefish, MT: Kessinger Publishing. ISBN 1-4191-0163-3. An armillary sphere is ideally suited as a sundial. With its hour face inscribed on the inner circular surface of the Equatorial ring—also known as the Equinoctial—the gnomon’s shadow sweeps uniformly along with time, allowing the hour markings to be equally spaced along the equinoctial ring. The British Museum has a collection of several armillary sphere rings that are incredibly well-crafted and detailed. When closed, they look like any other ring, but as the different bands are fanned out, the rings take on a unique quality. Built with anywhere between two to eight moving bands, these intricate pieces of jewelry would need to have been executed by skilled craftsmen. Museum numbers W.34-1939 to W.37-1938, a centre table, tripod table, armillary sphere and gate-leg table, were bought for the Museum by the National Art Collections Fund from the estate of Percival Griffiths (1861-1937). The choice was left to the Museum. A mirror, W.39-1938 was also given by his widow, Mrs Percival Griffiths, in his memory. Percival Griffiths, who lived at Sandridgebury, Hertfordshire, formed a collection of English furniture dating from the late 17th and early 18th century under the guidance of R.W. Symonds, the furniture historian and prolific writer on English furniture.The armillary sphere survives as useful for teaching, and may be described as a skeleton celestial globe, the series of rings representing the great circles of the heavens, and revolving on an axis within a horizon. With the earth as center such a sphere is known as Ptolemaic; with the sun as center, as Copernican. [1]

First ever Heritage Flame lit at Stoke Mandeville in a historic moment for Paralympic Movement". www.paralympic.org. 3 January 2014. Art historian Jessica Stewart writes that in the 17th century, rings such as the above specimen were “used by astronomers to study and make calculations. These pieces of jewelry were considered tokens of knowledge. Inscriptions or zodiac symbols were often used as decorative elements on the bands.”I think what’s most interesting (to me anyway) about these rings is the fact that they were, for some, important tools to grasp advanced concepts of astronomy, but for others, they were almost a way to brag about their own accomplishments. I mean, being an astronomer several centuries ago surely took plenty of work and a whole lot of learning (as is still true today), but scientists aren’t typically known for being braggadocious.

Zenith: in the horizon coordinate system, it is the position directly overhead on the celestial sphere. The zenith’s altitude is 90 o. Brashear, Ronald (May 1999). "Astronomiæ instauratæ mechanica by Tycho Brahe: Introduction". Special Collections Department. Smithsonian Institution Libraries . Retrieved July 11, 2020.It wasn’t until the middle of the 1500s CE that the basis of the instrument – a geocentric concept of the Universe – was seriously challenged by the Polish mathematician Nicolaus Copernicus. Even then, the instrument still continued to serve a useful purpose as a purely mathematical instrument. How does an armillary sphere work?