JUNTEN Astronomical Ring Men Women Armillary Sphere Ring for Couple Lovers Foldable Cosmic Finger Rings, Size 5-12

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a b Savage-Smith, Emilie (2017). "Of Making Celestial Globes There Seems No End" (PDF). Bulletin of the Scientific Instrument Society. No. 132: 1–9. Since ancient times, astronomers around the world have used models of the sky to make calculations. With the advent of the armillary sphere, stargazers were given a physical model to better visualize the lines of celestial longitude and latitude. Created independently in ancient Greece and ancient China, these armillary spheres consisted of spherical rings centered on either the Earth or the Sun. During the 16th and 17th centuries, these astronomy tools were sized down to become fashionable finger rings that moved just like regular armillary spheres. Enter the fictional world of James Bond, and you’ll find a number of handy dandy spy rings including one that doubles as a camera, and another capable of shattering bulletproof glass with a single twist. The Greek astronomer Hipparchus ( c. 190– c. 120 BC) credited Eratosthenes (276–194 BC) as the inventor of the armillary sphere. [11] [12] [13] [14] [15] Names of this device in Greek include ἀστρολάβος astrolabos and κρικωτὴ σφαῖρα krikōtē sphaira "ringed sphere". [16] The English name of this device comes ultimately from the Latin armilla (circle, bracelet), since it has a skeleton made of graduated metal circles linking the poles and representing the equator, the ecliptic, meridians and parallels. Usually a ball representing the Earth or, later, the Sun is placed in its center. It is used to demonstrate the motion of the stars around the Earth. Before the advent of the European telescope in the 17th century, the armillary sphere was the prime instrument of all astronomers in determining celestial positions.

The Arctic Circle E, and the Antarctic Circle F, each 23 1⁄ 2 degrees from its respective pole at N and S. Over the centuries the design of the armillary sphere has been modified to coincide with new astronomical discoveries. Before the advent of telescopes in Europe in the seventeenth century, the armillary sphere was the primary instrument of all astronomers for determining celestial positions.An armillary sphere (variations are known as spherical astrolabe, armilla, or armil) is a model of objects in the sky (on the celestial sphere), consisting of a spherical framework of rings, centered on Earth or the Sun, that represent lines of celestial longitude and latitude and other astronomically important features, such as the ecliptic. As such, it differs from a celestial globe, which is a smooth sphere whose principal purpose is to map the constellations. It was invented separately, in ancient China possibly as early as the 4th century BC and ancient Greece during the 3rd century BC, with later uses in the Islamic world and Medieval Europe. The armillary sphere is commonly used in heraldry and vexillology, being mainly known as a symbol associated with Portugal, the Portuguese Empire and the Portuguese discoveries.

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. Colure is one of two principal meridians (great circles) on the celestial sphere—equinoctial colure and solstitial colure.The whole fabric is supported on a pedestal N, and may be elevated or depressed upon the joint O, to any number of degrees from 0 to 90, by means of the arc P, which is fixed in the strong brass arm Q, and slides in the upright piece R, in which is a screw at r, to fix it at any proper elevation. While there is a good deal of evidence suggesting that ancient and medieval armillary spheres existed, much of it is not straightforward. Medieval texts often refer to instruments that could be either armillary spheres or celestial globes. Texts that specifically mention the construction and use of armillary spheres seem to be less common than those that deal with other astronomical instruments. Spheres and globes De Rose, L.: La sfera armillare di Solunto, in XVIII Seminario di Archeoastronomia, 19–20 marzo, Sestri Ponente, Genova (2016) Elements of the general description incorporate text from the Encyclopædia Britannica First Edition (1771). The tropic of Cancer C, touching the ecliptic at the beginning of Cancer in e, and the tropic of Capricorn D, touching the ecliptic at the beginning of Capricorn in f; each 23 1⁄ 2 degrees from the equinoctial circle.

The solstitial colure H, passing through the poles of the heaven, and through the solstitial points Cancer and Capricorn, in the ecliptic. Each quarter of the former of these colures is divided into 90 degrees, from the equinoctial to the poles of the world, for showing the declination of the sun, moon, and stars; and each quarter of the latter, from the ecliptic as e and f, to its poles b and d, for showing the latitude of the stars. The armillary sphere was reintroduced in the national arms and in the national Flag of Portugal in 1911. Aterini, B.: Geometric instruments for the orientation and measurement: the astrolabes. In: Advances in Historical Studies (AHS), 8, 58–78. Springer (2019b). http://www.scirp.org/journal/ahs. https://doi.org/10.4236/ahs.2019.81004 Lindberg, David C.; Shank, Michael H. (7 October 2013). The Cambridge History of Science: Volume 2, Medieval Science. Cambridge University Press. p.173. ISBN 978-1-316-02547-5 . Retrieved 15 May 2018.Tropic of Cancer: This small circle (also called the Northern Tropic) forms the northernmost latitude on earth at which the noontime sun can cross the zenith. This occurs around June 21 and is called the summer solstice in the northern hemisphere. A corresponding circle, also called the Tropic of Cancer, is formed by the projection of the earth’s Tropic of Cancer onto the celestial sphere. In ancient times, the sun passed through the zodiacal constellation of Cancer at this time of year — thus its name Cancer. The word “tropic” derives from the Greek word meaning turn — referring to the point on the sky where the sun changes direction and begins moving south as winter approaches in the northern hemisphere. Today, while precession (the wobble of the earth on its axis) has shifted the summer solstice into the constellational of Taurus, the solstitial sun remains in the astrological sign of Cancer, which is unaffected by precession. The Tropic of Cancer is currently at latitude 23 o 26.2’ N (23.44 o N). Like the obliquity, the latitude of the Tropic of Cancer varies from22.1 o Nand 24.5 o Nover about 41,000 years. The Tropic of Cancer is moving south toward the equator at about 50 feet per year. Zodiac: a band 18 o wide that is centered on the ecliptic. The zodiac comes from the Greek word for "circle of animals" that form the various constellation of stars in the eclilptic. The constellation of animals aries (the ram), taurus (the bull), cancer (the crab), leo (the lion), scorpius (the scorpion), and capricornus (the capricorn) were named at least a thousand years before by Babylonian and Chaldean astronomers. Since Roman times we also have constellation of libra (scales) and the representation of people in the form of aquarius (the water carrier), gemini (the twins), virgo (the virgin), and sagittarius (the archer). 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.

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. In the end of the 15th century, the armillary sphere became the personal heraldic badge of the future King Manuel I of Portugal, when he was still a Prince. The intense use of this badge in documents, monuments, flags and other supports, during the reign of Manuel I, transformed the armillary sphere from a simple personal symbol to a national one that represented the Kingdom of Portugal and in particular its Overseas Empire. As a national symbol, the armillary sphere continued in use after the death of Manuel I.Horizon: in astronomy, the unobstructed horizon is the circumference of the plane tangent to the earth’s surface at the observer’s location that intersects the celestial sphere. The horizon’s altitude is 0 o. For most of the second half of the 20th century this object was described by the Whipple Museum as having been made in about 1450. This would make it one of the earliest surviving demonstrational armillaries. Two other armillary spheres held in other museums date from this period, however this object is rather different from both of these. It is very difficult to date the armillary using the style of the lettering. The letter-shapes used to label the rings of the sphere suggest that it may have been produced at an even earlier date: perhaps in the 14th century.