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Astronomical Ring MiniatureH89 |
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| Although it is known as the Astronomic Ring Dial (Annulus Atronomicus), the complete name of this instrument used to determine the solar time and to make other astronomical measurements is the Universal Equinoctial Ring ... |
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Planisferic Astrolabe LHV 20H34 |
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| From the Greek "star searcher" this instrument was introduced in Europe by the Arabs. It became a vital tool for astronomers, astrologers and surveyors. Among other calculations one can establish the height of the Sun, t... |
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| Although known as the astronomical ring, it is principally employed as an ecuatorial solar universal quadrant. Its use was widespread during 18th century.It is composed of a ring that can be adjusted to various latitudes... |
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| Only perpetual calendars meet the basic condition to permit the deduction of any essential data from any other data (year, month, week and day).However, all the analog perpetual calendars known are hardly perpetual since... |
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