Newall Telescope
Once the world's largest refractor, now used for education.
The Newall Telescope, a 62.5-centimeter refractor now housed at the Penteli Observatory in Greece, was the world’s largest when completed in 1869. Thomas Cooke built it for Robert Stirling Newall, a Scottish engineer and amateur astronomer. Newall had purchased two large glass crystals—one crown, one flint—from Chance of Birmingham for £500 each, and Cooke initially promised delivery within a year, but the project took six years and was finished two years after Cooke’s death. The telescope first stood at Newall’s private observatory in Gateshead, but the site suffered heavy light pollution and frequent cloudy skies. Newall made few notable observations, the exception being detailed drawings of comet C/1874 H1 (Coggia) in 1874. He offered the telescope to Sir David Gill at the Cape Observatory, who declined due to the high cost of moving it to South Africa. In 1889, the year of his death, Newall gave it to the University of Cambridge, where his son Hugh Frank Newall worked. The instrument was relocated to Cambridge Observatory in 1891, with Hugh Newall covering the move and offering to operate it free for five years in exchange for land to build his residence nearby. From 1891 to 1911, Hugh Newall conducted spectroscopic and photometric observations, most notably discovering that the star Capella is a multiple star system. Frederick John Marrian Stratton continued the work after 1911, and the telescope remained scientifically significant until the 1930s, when newer instruments made it obsolete. By the 1950s, its dome was defective from long use, and Cambridge decided to donate it. The National Observatory of Athens expressed interest in 1955; after inspection, scientists deemed the telescope usable. A deal was finalized in 1957, influenced by the collaboration of Stavros Plakidis with Sir Arthur Eddington on long-period variable stars. The telescope became the largest in the Greek observatory’s collection and was moved to a less light-polluted site in Penteli, where Plakidis had been observing since 1936. A dedicated building, constructed with pentelic marble and a 14-meter dome, was completed in 1959. The ground floor can adjust vertically by about 5 meters. Scientific use ended in 1980 due to extreme light pollution, and since 1995 the telescope has served only educational purposes at the Penteli Observatory’s Visitor Centre.
Quick Facts
- Organization
- IAASARS of the National Observatory of Athens
- Location
- Penteli Observatory, Greece
- Built
- 1869
- Diameter
- 62.5 cm (24.6 in)
- Mounting
- German equatorial mount
- Style
- Refractor
Facts from the source article.
Lore & Background
The telescope was constructed after Robert Stirling Newall purchased two large crystals of crown and flint glass from Chance of Birmingham in 1862. He commissioned Thomas Cooke, recommended by fellow amateur astronomer Hugh Lee Pattinson, to build the world's largest telescope. Cooke initially estimated completion in under 12 months, but the telescope was finished six years later in 1869, two years after Cooke's death. It was installed at Newall's private observatory at Ferndene in Gateshead, but its location proved unsuitable due to light pollution and poor weather, limiting Newall's observations to notable drawings of comet C/1874 H1 (Coggia) in 1874. Newall offered the telescope to Sir David Gill at the Cape Observatory, but the cost of moving it was prohibitive. In 1889, Newall offered the telescope to the University of Cambridge, and it was relocated to the Cambridge Observatory in 1891, with his son Hugh Frank Newall covering the cost. Hugh Newall operated it for five years free of charge, conducting spectroscopic and photometric observations, most notably discovering that the star Capella is a multiple star system. After 1911, Frederick John Marrian Stratton continued the work, and the telescope remained scientifically significant until the 1930s, after which it became outdated. By the 1950s, its dome was defective, leading the Cambridge Observatory to donate it. The National Observatory of Athens acquired the telescope in 1957, influenced by the collaboration of Stavros Plakidis with Sir Arthur Eddington. It was moved to the Penteli Observatory in 1959, housed in a building made of pentelic marble with a 14 m dome. The telescope ceased scientific use in 1980 due to extreme light pollution and has been used only for educational purposes since the establishment of the Visitor Centre in 1995.
Reader's Guide
The Newall Telescope's significance lies in its status as the world's largest refracting telescope upon completion in 1869, a record it held for only two years until the US Naval 26-inch telescope was built. Despite its size, its initial placement at Gateshead was plagued by light pollution and poor weather, resulting in few notable observations. Its move to Cambridge Observatory in 1891 enabled important scientific work, including the discovery that Capella is a multiple star system, and it remained a key instrument until the 1930s. After becoming outdated, it was donated to Greece, where it served as the largest telescope of the National Observatory of Athens until 1980. Since then, it has been used solely for educational purposes, operated by the Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing. Its legacy is that of a pioneering instrument that, despite early setbacks, contributed to astronomical knowledge and continues to inspire through public education.
Did You Know?
- The telescope was built using two large glass crystals purchased for 500 pounds each.
- It was the largest refracting telescope in the world for only two years.
- It is housed in a building made of pentelic marble with an adjustable ground floor.
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