Eight-day wall-mounted astronomical regulator by Dent (Pip pip clock)

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Essential information

Opening times: 
10am–5pm daily
Royal Observatory, Meridian Line and Historic Royal Observatory, Time & Longitude gallery, Flamsteed House

Ever wondered what the famous pip-pip-pips sound heard on BBC radio marking the hour is?

Known originally as the Eight-day wall-mounted astronomical regulator, the clock is perhaps more commonly known as the pip-pip clock.  

This astronomical regulator was originally made for use in observing the Transit of Venus in 1874. 

In 1923 it became the source of the six-pip time signal used by the BBC. The clock sent electrical impulses down a telephone wire to the BBC for conversion into audio pips for radio broadcasts.

The clock was used for the pips from 1924 to 1990.