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H9903 Sidereal regulator clock, wood / metal / glass, made by Charles Frodsham, London, England, 1835-1885, used at Sydney Observatory, Sydney, New South Wales, Australia. Click to enlarge.

Regulator clock by Charles Frodsham

Charles Frodsham was born in 1810 and was the best known member of this family of watchmakers. He was renowned for the quality of his work and after his death in 1868 the company continued to produce quality clocks and watches well into the twentieth century.

After the death of John Roger Arnold in 1844, Charles Frodsham brought his business at 84 Strand, London. At first he signed his instruments 'J.R. Arnold - Chas Frodsham' but in 1857 he began working under his own name from the same address. In 1885 the company began engraving their clocks Frodsham and Co. although they still worked from the same address.

Very soon after he acquired Arnold's business Frodsham began to work with the Astronomer Royal, George Biddell Airy at Greenwich. This link between Greenwich and Frodsham is perhaps one reason Sydney Observatory also sought the services of Frodsham.

As a colonial enterprise Sydney Observatory received its first instructions from Airy and it is not surprising to find that in 1860 Airy also purchased this regulator clock on behalf of Sydney Observatory. The Government Astronomer at Sydney Observatory, William Scott noted in the 1860 Annual report that it had cost 70 pounds.

Originally this clock was set up to measure sidereal time and was linked to the transit observations. For this reason it was often referred to as the 'Transit Clock' by observatory staff. By 1861 it had been modified to enable it to be connected to the 'equatorial clock' by electrical current. In the 'Astronomical Results, 1879-80-81', the Government Astronomer, H C Russell the clock states the clock did not keep very good time and was sent in 1877 to Mr. Allerding for repairs. A slight fault with one of the pallets was polished out and this along with some other minor repairs improved the clocks rate.

This clock is one of the more significant in the collection as it had continuous use at Sydney Observatory for over one hundred years. In the nineteen twenties it was connected to the newly purchased Shorrt clock, 'S8', which delivered time signals.

This regulator clock is of national significance due to its pioneering role in Australian science and its association with Australia's earliest astronomers. It is also of international significant for its association with one of the nineteenth century's most acclaimed instrument makers.

Geoff Barker, Assistant Curator, Total Asset Management Project, March 2008

Antiquorum Catalogue, 'Charles Frodsham', Longitude at the Eve of the Third Millennium, Antiquorum, Geneva, 1999
Bhathal, R., Australian Astronomer; John Tebbutt, Kangaroo Press, Kenthurst, NSW, 1993
Mercer, Tony, Chronometer Makers of the World, N.A.G. Press and Tony Mercer, 1991
Mercer, Vaudrey, The Frodshams; the Story of a Family of Clockmakers, The Antiquarian Horological Society, Kent, England, 1981
Russell, H C, 'Sydney Observatory; Astronomical Results, 1879-80-81' Charles Potter, Government Printer, 1893
Scott, William, Annual Report 1865, Sydney Observatory, 1865


Object No.


Object Statement

Sidereal regulator clock, wood / metal / glass, made by Charles Frodsham, London, England, 1835-1885, used at Sydney Observatory, Sydney, New South Wales, Australia

Physical Description

Sidereal regulator clock, wood / metal / glass, made by Charles Frodsham, London, England, 1835-1885, used at Sydney Observatory, Sydney, New South Wales, Australia

A sidereal regulator clock consisting of a rectangular wooden long case with a hinged door at the front. A glass panel in the door allows a weighted pendulum to be seen. There is a large circular clock dial at the top of the case.The dial has one hand and is numbered from '5' to '60'. Two smaller dials are contained within the large dial. The upper dial is marked from '10' to '60' while the lower dial is marked from '0' to '23'. Both the smaller dials have one hand each. The clocks mechanism sits behind the clock dials.

Observatory Stock No. 987 Observatory stock number 30.



1860 mm


425 mm


260 mm



The clock was made by Charles Frodsham, 84 The Strand, London, England between 1835 and 1885.



The clock was used at Sydney Observatory, Sydney, New South Wales, Australia as part of the radio time signal system and associated with electric panels on the west wall of the Transit Room of the Observatory. After the introduction of the Atomic Clock (H9898), the regulator clock was still maintained as a stand-by (blue file).
Observatory Stock Number 30 (blue file).

Cite this Object


Regulator clock by Charles Frodsham 2021, Museum of Applied Arts & Sciences, accessed 5 March 2021, <https://ma.as/258835>


{{cite web |url=https://ma.as/258835 |title=Regulator clock by Charles Frodsham |author=Museum of Applied Arts & Sciences |access-date=5 March 2021 |publisher=Museum of Applied Arts & Sciences, Australia}}


This object record is currently incomplete. Other information may exist in a non-digital form. The Museum continues to update and add new research to collection records.