Wallingford Astronomical clock

The rectangulus was an astronomical instrument made by Richard of Wallingford around 1326. Dissatisfied with the limitations of existing astrolabes, Richard developed the rectangulus as an instrument for spherical trigonometry and to measure the angles between planets and other astronomical bodies. This was one of a number of instruments he created, including the Albion, a form of equatorium, and a famously complicated and expensive Horologium (astronomical clock).

But perhaps Richard of Wallingford is best known for the astronomical clock he designed, while he was abbot of St Albans, which is described in the Tractatus Horologii Astronomici (1327).

The clock was completed about 20 years after Richard’s death by William of Walsham but was apparently destroyed during Henry VIII‘s reformation and the dissolution of St Albans Abbey in 1539. His clock almost certainly was the most complex clock mechanism in existence at the time in the British Isles, and one of the most sophisticated ones anywhere. The only other clocklike mechanism of comparable complexity that is documented in the 14th century is the astrarium by Giovanni de Dondi

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