Grubb Parsons
 Installation of Grubb's Great Melbourne Telescope, once the largest steerable telescope globally, in 1868 | |
| Grubb Parsons | |
| Formerly | Grubb Telescope Company |
| Industry | Optical engineering |
| Founded | 1833 in Dublin, Ireland |
| Founder | Thomas Grubb |
| Defunct | 1985 |
| Headquarters | Dublin (1833-1918) St Albans (1918-25) Newcastle (1925-85) |
Key people | Howard Grubb Charles Parsons |
| Products | Telescopes Periscopes Lenses |
Number of employees | 150 (1955) |
| Parent | C.A. Parsons & Company (1925-85) |
Grubb Parsons (officially known as 'Sir Howard Grubb, Parsons and Co. Ltd.') was a prominent telescope manufacturer operating throughout the 19th and 20th centuries. The firm was responsible for producing numerous large-scale research telescopes, several of which held records as the largest of their kind during their respective eras.
Established in 1833 by Thomas Grubb under the name Grubb Telescope Company in Dublin, leadership transitioned to his son Howard Grubb during the 1860s. The company crafted numerous significant telescopes, including landmark 19th-century instruments such as the 1868 Great Melbourne Telescope (a reflecting telescope), a refractor for the Vienna Observatory completed in 1878, and the 1893 Greenwich 28 inch refractor. Throughout and following the First World War (1914–18), production expanded to submarine periscopes, coinciding with a relocation to St Albans in 1918.
In 1925, after acquisition by Charles Algernon Parsons, the company was renamed Grubb Parsons and shifted operations to Newcastle upon Tyne. During the 20th century, they delivered several major research telescopes such as the Isaac Newton Telescope (1965), the Anglo-Australian Telescope (1965), and the UK Infrared Telescope (1979). The firm's final undertaking was the construction of the William Herschel Telescope in 1985, after which it ceased operations.
Under Thomas Grubb
The origins of the Grubb Telescope Company trace back to its founding in Dublin by Irish engineer Thomas Grubb in 1833. Initially, his precision engineering business specialized in cast iron goods including billiard tables and printing machinery designed for banknotes. Driven by a personal passion for optics and connections with astronomer Thomas Romney Robinson, Grubb’s first telescope was a refracting model installed at a public observatory in Portobello, Dublin.
One of the company's earliest significant contracts involved manufacturing the mount for a telescope at Markree Observatory, finalized in 1834 as what was then the largest refracting telescope worldwide. Edward Joshua Cooper, owner of Markree, procured lenses from Robert-Aglaé Cauchoix of Paris and commissioned Grubb to supply mechanical components featuring an equatorial mount equipped with a clock drive—an innovative solution given its scale.
In 1835, Grubb delivered a reflecting telescope to Armagh Observatory, managed by Robinson. This instrument employed a Cassegrain optical design paired with an equatorial mount—a pioneering combination for large telescopes that later gained widespread acceptance.
The company further expanded its international reach with projects such as the Sheepshanks equatorial refractor for London's Royal Observatory Greenwich in 1838 and a refractor for the United States Military Academy at West Point completed in 1840; both utilized Cauchoix lenses. Additionally, during the mid-19th century, they produced compound microscopes alongside their astronomical instruments.
Under Howard Grubb
In 1865, Thomas Grubb was joined by his son, Howard Grubb, as he approached retirement; Thomas stepped down in 1868 and passed away in 1878. Under Howard's leadership, the firm’s reputation for producing superior optical instruments was significantly enhanced, culminating in his knighthood in 1887.
The company made important contributions to early astronomical spectroscopy by manufacturing various spectroscope models, including distinguished two- and six-prism versions completed by 1867.
One of the company’s landmark achievements in 1868 was the construction of the Great Melbourne Telescope, which at the time was the world’s second largest and largest fully steerable telescope, featuring a primary mirror made of speculum. Notable subsequent commissions included a speculum reflector for William Huggins’ private observatory in 1871, a reflector for the Royal Observatory, Edinburgh in 1872, and a refractor for the Vienna Observatory in 1878—then recognized as the largest refractor globally and renowned for its exceptional optical quality.
These flagship instruments elevated the company's standing, leading to further prestigious orders such as a telescope for William Edward Wilson’s private observatory (1881), a heliostat supplied to the Smithsonian Astrophysical Observatory (1890), and the UK's largest refractor installed at Greenwich (1893). In 1887, Grubb produced seven identical 13-inch astrographs designed for the international Carte du Ciel initiative aimed at standardizing photographic plates. Additional significant products included a reflector for Greenwich (1896), an 18/24-inch double refractor for the Cape of Good Hope Observatory (1897), and a similar instrument for Oxford's Radcliffe Observatory (1901).
Following the invention of the submarine periscope in 1902, Howard Grubb secured several patents improving its design, which led to the company shifting focus toward periscope production by 1914. During World War I, periscopes manufactured by Grubb were installed on most British submarines; due to security concerns, production was moved to St Albans in 1918. Despite Howard Grubb’s efforts to revive large telescope manufacturing after the war, military contract losses caused financial difficulties. Several projects faced delays or remained unfinished during this era, including a reflector ordered in 1909 for Chile’s National Astronomical Observatory that only became operational by 1925.
Grubb Parsons
By 1925, with Howard Grubb aged 81 and facing near financial collapse, ownership transferred to Charles Parsons, an Anglo-Irish engineer with familial ties to telescope construction through his father, William Parsons, builder of the Leviathan of Parsonstown. Parsons rebranded the enterprise as Grubb Parsons and relocated operations to Newcastle-upon-Tyne, where his other engineering ventures were based.
The first significant telescope completed under Parsons’ direction was a reflector delivered to the Royal Observatory Edinburgh in 1930. The following year, a comparable instrument known as the Yapp telescope was commissioned by the Royal Greenwich Observatory. In 1931, Grubb Parsons supplied a reflector and a 24/20-inch double refractor to the newly established Stockholm Observatory.
After Charles Parsons’ death in 1931, Grubb Parsons continued as a subsidiary within his engineering firm, C. A. Parsons and Company. In 1938, it expanded by acquiring the telescope manufacturing division of Cooke, Troughton & Simms.
The company leveraged design uniformity with six nearly identical telescopes featuring apertures of approximately , installed at observatories worldwide: David Dunlap Observatory (Canada, 1935), Radcliffe Observatory (South Africa, completed 1938), Mount Stromlo Observatory (Australia, 1955), Haute-Provence Observatory (France, 1956), Okayama Observatory (Japan, 1960), and Helwan Observatory (Egypt, 1963). Additionally, smaller telescopes were produced including a for Cambridge Observatory (UK, 1955), one for the South African Astronomical Observatory (1963), and another for the Dominion Astrophysical Observatory (Canada, 1961).
A major undertaking was constructing the Isaac Newton Telescope for the Royal Greenwich Observatory, completed in 1965 at Herstmonceux Castle. Due to unsuitable location conditions, it was relocated between 1979 and 1984 to the Roque de los Muchachos Observatory in the Canary Islands; during this move Grubb Parsons upgraded its mirror to .
Transitioning from mechanical designs towards optical systems manufacture, Grubb Parsons produced thousands of mirrors, lenses, and prisms used in spectrometers and smaller telescopes. They crafted and polished the primary mirror for the Anglo-Australian Telescope (AAT) at Siding Spring Observatory in 1965; however, other companies handled its design and mounting. The firm also constructed the UK Schmidt Telescope in 1973 and supplied optical components for the UK Infrared Telescope (1979), which was then recognized as the largest infrared telescope globally. Smaller projects included producing optics for both the Jacobus Kapteyn Telescope (1979) and the Danish National Telescope (1976).
Grubb Parsons continued operations until 1985; their concluding project was delivering the William Herschel Telescope.
Historiography
The remaining records of the company are preserved at the Tyne and Wear Archives, which is part of the Discovery Museum located in Newcastle.
Ian Glass, an expert in the history of astronomy, chronicled the firm's development during the eras of Thomas and Howard Grubb, focusing mainly on their letters. Additionally, Glass assembled detailed catalogues listing telescopes manufactured by both Grubb and Grubb Parsons.
A partial account of the company's history during the Parsons period was written by George Sisson, who served as its final managing director.
See also
- List of largest optical telescopes in the 19th century
- List of largest optical telescopes in the 20th century
- T. Cooke & Sons - a British telescope manufacturer established in 1837, contemporaneous with Grubb Parsons