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.
The gallery below involving astronomical clocks represents models which were first started during the Byzantine era thanks to intricate designs to document the
dynamic nature of the Solar System's primary bodies as viewed from Earth, namely the Sun and Moon, with further efforts to depict the zodiacal constellations
and the travels of the Sun and Earth across the ecliptic. These engineering marvels represent a European phenomenon and preoccupation with a particular
concentration in Italy, Britain and France.
A more antiquated effort to document time using the heavens above was initiated by the ancient Greeks around 200 to 150 BC with the introduction of the asrtrolabe
and which gained particular prominence about 800 AD and thereafter when it was widely adopted by the Islamic World in its efforts to precisely identify daily
sunrise and sunset times due to religious obligations (vis a vis prayer times). The gallery below also includes astrolabes as well as their simpler counterparts
(ie quadrants) with the samples from England, France and Italy having a dedicated (hyperlinked) page due to the shear volume of items available and which would
otherwise overwhelm the country-specific collections below.
Each sample image below is hyperlinked and leads to a dedicated page with greater resolution and further background information.
(Sample astrolabes and astrolabe quadrants for England, France and Italy below are hyperlinked to dedicated pages for those countries due to a large volume of items.)