Although time and its measurement is a fundamental component of human life, a special type of clock which takes matters to the next level is the so-called
astronomical clock and whose purpose is not to measure time per se but to convey astronomical information and, in particular, the relative position of the
Sun and Moon as well as the zodiacal constellations and, in some cases, the position of the planets all as a function of time.
The oldest such effort to effectively emulate the overhead celestial sphere (ie a mini-planetarium) is the
Antikythera Mechanism which was discovered in 1901 totally by
accident by sponge divers off the coast of the Greek island of Antikythera. It has been dated to approximately 80 BC and it is believed to be the work of
Poseidonius of Rhodes. The Antikythera Mechanism is currently on display
at the National Archaeological Museum in Athens, Greece.
Note: The astrolabe is yet another instrument constructed to describe the overhead sky and monitor time. Some versions also
have religious implications such as the Muslim Qibla where a magnetic compass on the back side of the astrolabe helps the user identify the proper orientation
so as to point at the holy city of Mecca for prayer. Astrolabes were first developed by the Greeks around the second century BC and were slowly adopted
throughout the known world of the time by numerous cultures. Astrolabes describe the position of the planets and prominent stars visible at a particular
latitude (see curved markings on each dial in the photo below) and, by extension, act as time-keeping devices. Similarly, they assist in the time of expected
sunrise which is vital for the Muslim religion and the timing of morning prayers at dawn ("fajr") and thereafter at noon ("dhuhr"), afternoon ("asr"), sunset
("maghrib") and nightfall ("isha"). As a result, it is no surprise that the overwhelming number of astrolabes found in museums around the world are
islamic in origin given the adoption of these instruments from around 700 AD and thereafter by the Islamic World. Today's planispheres can be said to be a
direct extension of the ancient astrolabe, for they function and inform the user of precisely the same information sought-after by users many centuries ago.
The very impressive brass astrolabe below is one of approximately twenty astrolabes on display at Museo Galileo in central Florence. The astrolabe was crafted
by the well-known German scientific instrument maker Christoph Schissler (1531-1608 AD) whose workshop was based in Augsburg, Germany with over 100 of his
high-precision instruments residing in collections in various museums around the world. The astrolabe is 215 mm in diameter with the back side carrying Schissler's
signature and date of manufacture, namely 1560 AD, with the astrolabe making its way to Florence in the 17th century thanks to the efforts of Prince Matias de'
Medici (1613-1667 AD). The astrolabe is accompanied by a single latitude plate (latitudes 45° and 48°) and which corresponds to Bavaria, thus making the astrolabe
planespheric in nature, for it projects the three-dimensional celestial sphere onto a two-dimensional plane. During the Middle Ages, three-dimensional astrolabes
were first described but only one such example seems to have survived to present day and which can be found at the History of Science Museum in Oxford, England.
The historic center of Florence is characterized with a number of epic museums (with very impressive collections) which are a must-see while visting the city.
One such museum is the impressive Museo Galileo (Galileo Museum) and which was originally named Museo di Storia della Scienza (History of Science Museum)
owing to its rich collection of scientific instruments including many astrolabes, horary quadrants, nocturnals, sundials, armillary spheres as well as Galileo's
instruments including his telescopes. The museum's collections are displayed across two floors and eighteen thematic rooms including "Astronomy and Time"
(Room II), "The Science of Navigation" (Room V), "The Science of Warfare" (Room VI), "Galileo's New World" (Room VII), "After Galileo: Exploring The Physical
and Biological World" (Room IX), "The Spectacle of Science" (Room XI), "Measuring Natural Phenomena" (Rooms XV and XVI) and "Science at Home" (Room XVIII).
Museo Galileo is open daily between 09:30 and 18:00 except for Tuesdays when it is open 09:30 to 13:00. Admission costs 13 euro and one can easily be engaged
for a number of hours. The Museo Nazionale del Bargello with its magnificent collection of art and sculpture masterpieces is less than 400 meters to the north and
only a few minutes away by foot with two astrolabes and an astrolabe quadrant in its collection and on display whereas the Fondazione Scienza e Tecnica with its
impressive collection of scientific instruments from the nineteenth and twentieth centuries is 1200 meters further north and boasts a Galleria dell'Astronomia
with a rich suite of astronomical instruments including an astrolabe.
Note: For additional results involving astronomical clocks and astrolabes from around the world, please click
here.
Body: Sun Mass: 332,900 x Earth Mass Eq Diameter: 109.1 x Earth Distance: 149 million km RA / Dec: 23h 41m 41s / +89° 19' 51" Diameter: 32.16' Magnitude: -26.8 |
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Date: April 20, 2024 Location: Museo Galileo, Florence, Italy Equipment: Canon EOS 6D Baader BCF2 Filter Canon EOS EF 50mm/f1.8 USM @ f4.0 Exposure: 1 x 1/200 sec ISO 6400 JPG Fine Image Format 5472x3648 Image Size Custom White Balance Continuous Servo Mode Manual Mode Software: Photoshop CS6 Processing: White Balance Adjustment Resampling JPG Compression |