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: Located in the heart of Brescia's historic center and perhaps the highlight of Piazza della Loggia, one will find the impressive 15th century renaissance building with the dominating clock tower on the eastern side of the square. The tower commonly referred to as "Torre dell'Orologio" was built between 1540 and 1550 AD by one of the architects of Piazza della Loggia and hosts the impressive astronomical clock of Brescia, built in 1543, as seen below.

The outer ring is divided into 24 segments representing 24 hours (ie one full day) and is labelled accordingly with the roman numerals I through XXIV. A dial which carries the Sun rotates by depicting the time of day on the outer dial while simultaneously indicating the Sun's position along the zodiac courtesy of the ring which immediately follows where the twelve constellations are depicted whereas the following ring with the roman numerals I through XXX indicates the current date of the month. The innermost ring is used to denote the age of the Moon where a new Moon is indicated by the figure of 00 (immediately below the golden Sun) whereas a full moon is diametrically across and labelled as 12, thus appropriately representing the physical location of the Moon during its monthly rotation around Earth while also respecting the Sun-Earth-Moon geometry. Finally, the phase of the Moon is depicted by the partially covered (lunar) disk.

The text references to "Sestile", "Trino" and "Quadrante" visible at the core of the clock accompanied by various radiant vectors are used to describe angles between planets (aka "aspects") which are of interest in astrology.

Note: For a view of the astronomical clock using much greater focal length, please click here and here.

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