An eight-day astronomical regulator signed ‘E. Dent & Co. / 61, Strand London 2009’. A conventional weight-driven regulator with dead-beat escapement and jewelled pallets; seconds, quarter-hour and hour contacts; zinc-and-steel compensated pendulum with hit-and-miss synchronizer and a Synchronome magnetic corrector. It is one of a series of 12 clocks made by Dent specially for the British 'Transit of Venus' expeditions of 1874. Number 2009 was used by Captain Orde Browne to observe the transit at Mokattam, Egypt, and was afterwards used at Greenwich in the South-East Equatorial dome with the 12.8-inch, and later with the 28-inch telescopes.

In 1940, the clock was fitted with the present electrical contacts, an electro-magnetic corrector device and a hit-and-miss synchronizer so that it could be controlled by a Shortt free-pendulum clock. It was then set up at Edinburgh as part of a reserve station for broadcasting the six-pips time signal in case the regular station at Abinger was damaged by enemy action. In the event, the reserve station was not needed.

The firm of Dent & Co. originated with Edward John Dent (1790–1853), one of the most celebrated of all the 19th century chronometer and precision clock makers. Dent built up a strong relationship with the Astronomer Royal and the Royal Observatory. He received considerable patronage from both. In the 1840s Dent expanded his already healthy business, having no fewer than three London premises. He also founded a turret clock manufactory which would produce one of the most famous clocks in the world, the Great Clock at Westminster, familiarly known as ‘Big Ben’ (actually the name applied to the hour bell). However, the work was only completed after Dent’s death. The firm of Dents continued in business for many years, only finally closing in the 1970s.