Hemisferium Nautical Astrolabe Key ring
The nautical astrolabe is a simplification of the planispherical or astronomical astrolabe and its fundamental purpose is to determine the latitude of a ship by observing the altitude of the sun or other stars such as the Pole Star. The nautical astrolabe has a much heavier design than a typical astrolabe of the time to survive the rough sea conditions and compensate for the movement of the ship.
This instrument is a reproduction of a Portuguese marine astrolabe that was owned by a Dundee skipper, A. Smyton. The original piece is at the Art Gallery and Museum of Dundee, in Scotland.
Astrolabe, from the Greek, “star searcher”, was introduced to Europe by the Arabs in the early 12th century. It became a vital tool for astronomers, astrologers, and surveyors. This astronomical computer was used to estimate the time, to measure heights of celestial bodies and geographical accidents, determine the local latitude, estimate the sunrise and sunset time and to draw horoscopes.
The astrolabe's importance not only comes from the early development of astronomy but is also effective for determining latitude on land or calm seas. It was less reliable on the moving deck of a ship in rough seas, so the mariner's astrolabe was developed to solve that problem.
In the 9th century, Muslim astronomers improved the device by introducing angular scales and azimuth lines which added to its beauty.
To use an astrolabe, the moving parts are first set to a specific date and a specific time. Once set, solar system objects are represented (both visible and invisible) in their relative positions on the instrument. The typical astrolabe was not a navigation tool, however. The similarly named 'mariner's' astrolabe was used for this purpose and was used widely in the European Renaissance.
This new astrolabe is made by hand in the same way as astrolabes were over a thousand years ago. However, the map of the sky is up to date for the 21st century.
Attention to detail, historical interest and its beautiful design is brought to life in this elegant astrolabe. It comes complete on a keyring to take out wherever you decide to adventure and add a unique element to your keys.
The astrolabe measures 25mm across, and 1.8mm thick.