Shuckburgh telescope

Shuckburgh telescope
Alternative names	Shuckburgh equatorial refracting telescope
Location(s)	United Kingdom
Telescope style	optical telescope
Diameter	4.1 in (0.10 m)
Mounting	equatorial mount
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The Shuckburgh telescope or Shuckburgh equatorial refracting telescope was a 4.1 inches (10.4 cm) diameter aperture telescope on an equatorial mount completed in 1791 for Sir George Shuckburgh (1751–1804) in Warwickshire, England, and built by British instrument maker Jesse Ramsden (1735–1800).^[1]^[2]^[3]^[4]^[5] It was transferred to the Royal Observatory, Greenwich in 1811 and the London Science Museum in 1929.^[2] Even though it has sometimes not been regarded as particularly successful, its design was influential.^[3] It was one of the larger achromatic doublet telescopes at the time, and one of the largest to have an equatorial mount.^[2] It was also known as the eastern equatorial for its location.^[6]

It was pictured in the Rees Cyclopedia of the early 1800s.^[7] It was early pictured in Philosophical Transactions, published in 1793.^[8]

At the Royal Observatory in Greenwich, it was for a time installed in the North Dome, although this had a Sky view partially obscured by the Octagon room.^[9]^[10] It was earlier installed as an alt-az mount in the South dome at Greenwich, which in 1838 is where the then-new 6.7 inch aperture Sheepshanks refractor was installed.^[11]

The telescope tube is 5 feet four inches long (about 1.6 meters).^[9] The focal length was the same for this telescope, with object glass being doublet of 4.1 inch (~10.4 cm) aperture.^[10]^[12]

Shuckburgh placed an order with Ramsden for the telescope in 1781, and it was delivered for his observatory ten years later.^[13] He also ordered a clock from John Arnold & Son to use with the telescope.^[13] The telescope was installed at Shuckburgh Hall, in Warwickshire, United Kingdom.^[13]

Observations

The Shuckburgh/ Eastern telescope was used for the 1832 transit of Mercury equipped with a micrometer by Dollond.^[14] By observing the transit in combination with timing it and taking measures, a diameter for the planet was taken. They also reported the peculiar effects that they compared to pressing a coin into the Sun. The observer remarked:

I afterwards observed, that immediately around the planet there was a dusky tinge, making it appear as if, in a small degree sunk below the sun's surface;^[14]

The Shuckburgh and the western equatorial at Greenwich are recorded as having been used for observations of the 1835 apparition of Halley's Comet.^[15]

The Shuckburgh, also called the "Eastern Equatorial" at the time Halley's comet was sometimes used with a micrometer microscope.^[6] For the observations of Halley's 1835, the Transit and Arnold 1 and 2 clocks were used.^[6] Observations were recorded in August, September, and October, but it could not view the comet after October 19, because its view was blocked by another part of the observatory building.^[6]

The Shuckburgh is also reported to have been used for observing the occultation of stars by the Moon and observing the moons of Jupiter.^[16]