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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 the limit of their calculations is about 50 years.  Our calendar starts at January 1, 1600, and ends at December 31, 2799. It is based...

  • It consists on a Perpetual Moon phases calendar with a Tidal abacus or computer on the back. This instrument was conceived to address the need to predict the time of tidal changes. It draws on their intimate association with the rotation of the Moon, which influences the tides as it revolves around the Earth. Knowledge of the lunar phases has been of...

  • From first scientific toys that used animated images to modern movies, retinal persistence has been fundamental to fooling the mind into believing that a series of static images are in motion. In1834, the English mathematician George Horner proposed a practical apparatus based on the phenakistoscope of Plateau and Stampfer (1830). It eliminated the need...

  • This instrument is a reproduction based on two Gunter (E. Gunter, 1581-1626) quadrants made in the mid-eighteenth century. The original pieces, made by unknown English authors, are at the Greenwich National Maritime Museum, London. On the face side, the instrument presents a local height quadrant furnished with a pinule system for establishing the Sun’s...

  • In Europe, the astrolabe became the vital tool for astronomers, astrologers and surveyors until the end of the 17th century, when it was replaced by more precise instruments. In the Arab world its use continued until the 19th century. This Plansiferic Astrolabe is based on an instrument made by German manufacturer. G. Hartmann which can be found at the...

  • The piece is a replica of a Nocturnal and Tide Computer from 1570, signed by Humphrey Cole. It is one of the first BritishRenaissance´ instruments.The original can be found in the British Museum, London. One of its faces is a Nocturnal and the other is a Tide Computer. The Nocturnal or star clock is an artifact that is used to obtain the time at night...

  • This dial of German origin is an Universal sundial like the Beringer quadrant. It also has a moveable scale of latitudes to be set for the measure.  Equinoctial sundial, known as “Augsburg clock”. The original was made by Iohann Georg Vogler (1720-1765) who belonged to the fourth generation of a legendary line of goldsmiths in Augsburg, Germany. It is in...

  • This instrument is really a reproduction of an Octant of the mid-17th century. By semi-accurately measuring the height of stars or the sun, the Octant allows navigants to determine geographic latitude. In 1731 John Hadley (England) and Thomas Godfrey (Philadelfia, U.S.A.), demonstrated the Octant, independently. The arc of an Octant is 45º or 1/8 of a...

  • This nocturnal watch ––horologium nocturnale–  is an astronomical instrument used to measure the time through the observation of the Pole Star and the position of brigth stars in the celestial sphere.  This nocturnal is a reproduction of the one made in 1570 by Girolamo della Volpaia  (currently at the Galileo Museum in Florence, former History of...

  • 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, a meridian ring showing the latitude scale, a moveable hour ring and a central, grooved bar that is graduated for the months of the...

  • This scientific toy with animated images also relies in retinal persistence to make us believe we are seeing images in motion. The praxinoscope was patented by the Frenchman Emile Reynaud in 1877, who was looking to overcome the deficiencies of the zoetrope, the most popular at the time. His apparatus was the first to eliminate the distorted view of the...

  • This scientific toy with animated images also relies in retinal persistence to make us believe we are seeing images in motion. The praxinoscope was patented by the Frenchman Emile Reynaud in 1877, who was looking to overcome the deficiencies of the zoetrope, the most popular at the time. His apparatus was the first to eliminate the distorted view of the...

Showing 1 - 12 of 26 items