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Full Description

Brand: Geodus
Diameter: 20 cm (8 in.)
Overall height: 25 cm (10 in.)
Materials: metal
Modern Astrolabe (large size).




Reproduction of an astrolabe realized by Arsenius in 1602.
An original specimen of this astrolabe is carefully guarded in the Museum of the History of Science in Oxford.
This astrolabe is shipped with 2 additional Plates (45° and 50°).



Function.

An astrolabe is a very ancient astronomical computer for solving problems relating to time (what time is it ?) and the position of the Sun and stars in the sky.

Astrolabes are used to show how the sky looks at a specific place at a given time.
This is done by drawing the sky on the face of the astrolabe
To use an astrolabe, you adjust the moveable components to a specific date and time. Once set, much of the sky, both visible and invisible, is represented on the face of the instrument.
Typical uses of the astrolabe include finding the time during the day or night, finding the time of a celestial event such as sunrise or sunset and as a handy reference of celestial positions.
The typical astrolabe was not a navigational instrument although an instrument called the mariner's astrolabe was widely used in the Renaissance.




History.

The history of the astrolabe begins more than two thousand years ago.
The principles of the astrolabe projection (stereographic projection) were known before 150 B.C., and true astrolabes were made before A.D. 400.
The astrolabe was highly developed in the Islamic world by 800 and was introduced to Europe from Islamic Spain (al-Andalus) in the early 12th century.
It was the most popular astronomical instrument until about 1650, when it was replaced by more specialized and accurate instruments.



Accuracy.

The sky map of this astrolabe has been updated from the one of the 16th century.

It's accuracy is:

for the latitudes 39° to 42° (41° Mater), 43° to 47° (45° Plate), 48° to 52° (50° Plate)

for the North latitudes out of this interval.



Attention to detail, historical interest, beauty of forms characterize this very fine Astrolabe, shipped complete with a hardwood display stand and a user guide ( in english in spanish ).


N.B.: This is the replica astrolabe used in the TED video presentation from Tom Wujec.
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