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 case of mathematical equipment below includes a wide variety of instruments made of brass with the center piece being the astrolabe from 1659 AD. The construction of these instruments is attributed to the grandfather and grandson duo of Giacomo (1639-1689 AD) and Domenico (1669-1744 AD) Lusverg whose workshop was based in Rome, Italy. The box measures 530 mm by 365 mm and is comprised of three trays with the upper tray containing the aforemnetioned astrolabe as well as various compasses, inclinometer, calipers and protactor amongst others. The astrolabe is 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: Due to the wide field nature of the equipment case below, the resampling for web use leads to a loss of fine detail which is otherwise available when examining the original high-resolution image. For two sample segments at 100% resolution, please click here and here.

Note: For additional results involving astronomical clocks and astrolabes from around the world, please click here.