Wells Cathedral clock

The Wells Cathedral clock is an astronomical clock in the north transept of Wells Cathedral, England. The clock is one of the group of famous 14th to 16th century astronomical clocks to be found in the West of England. The surviving mechanism, dated to between 1386 and 1392, was replaced in the 19th century, and was eventually moved to the Science Museum in London, where it continues to operate. The dial represents the geocentric view of the universe, with sun and moon revolving round a central fixed earth. It may be unique in showing a philosophical model of the pre-Copernican universe.

Another dial is mounted on the outside wall, driven from the same mechanism. This was first installed in the 14th or 15th centuries, but has been restored a number of times.

The dial proposes a model of the universe. Against a background of stars, the sun (the large gilded star on the outer ring) moves in a circle, and indicates the time using the 24-hour analogue dial, which is marked in Roman numerals from I to XII, then from I to XII again. Noon is at the top of the dial reflecting the position of the sun in the sky at this time.

In the corners, four angels hold the four cardinal winds. These may be generating the power that makes the universe operate.

The minutes are indicated by a smaller star on the ring inside.

The inner circle shows the moon. A pointer indicates the age of the moon, between 1 and 30 days. The black and white disk above the centre shows the moon's phase. The white disk rotates once in a synodic month. The inscription around the moon phase indicator says sphericus archetypum globus hic monstrat microcosmum, which translates as This spherical globe here shows the archetypal microcosm. Howgrave-Graham suggests that the scribe erroneously put microcosmum, when macrocosmum is the more obvious word. Opposite the moon circle is a weighted pivoted disc, containing a small painting of Phoebe, representing the moon. The inscription reads: Sic peragrat Phobe, or So progresses Phoebe.

At the centre of the dial, the ball represents the earth, and the clouds suggest the same.

...
Wikipedia