Isaac Roberts' Observatory
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Isaac Roberts' Observatory was an
observatory An observatory is a location used for observing terrestrial, marine, or celestial events. Astronomy, climatology/meteorology, geophysical, oceanography and volcanology are examples of disciplines for which observatories have been constructed. His ...
, installed in the private home of the British astronomer
Isaac Roberts Isaac Roberts FRS (27 January 1829 – 17 July 1904) was a Welsh people, Welsh engineer and businessman best known for his work as an amateur astronomer, pioneering the field of astrophotography of nebulae. He was a member of the Liverpool As ...
. It was in
Crowborough Crowborough is a town and civil parish in East Sussex, England, in the Weald at the edge of Ashdown Forest in the High Weald Area of Outstanding Natural Beauty, 7 miles (11 km) south-west of Royal Tunbridge Wells and 33 miles (53 ...
,
Sussex Sussex (), from the Old English (), is a historic county in South East England that was formerly an independent medieval Anglo-Saxon kingdom. It is bounded to the west by Hampshire, north by Surrey, northeast by Kent, south by the English ...
, and was active from 1890, when Roberts installed it, until his death in 1904. The observatory appears in the List of observatory codes of the
Minor Planet Center The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory. Function ...
with the code 001.


History

Roberts began his astronomical observations in 1878, and early on saw the need to have the best observation conditions to make photographic records. This factor, coupled with his chronic bronchitis, which meant he needed a better climate for his health, motivated him to look for a new location suitable for his observations. In 1885 he acquired copy of ''Observations upon the Topography and Climate of Crowborough Hill, Sussex'' by Charles L. Prince, describing and extolling the conditions of the area, precisely those he needed. The local landowner sold to Roberts part of his property, four acres (1.6 hectares), where he built his house including a domed observatory to accommodate his telescopes. In 1890 Roberts, who called the house ''Starfield'', moved in. In his new house and observatory he continued his work—which earned him, among others awards, the Gold Medal of the Royal Astronomical Society of London—until his death in 1904.James, ''Dr Isaac Roberts...'', p. 122 After his death the house changed hands several times until, in 1928, it was bought by local government and turned into offices. In 1935 the offices were extended resulting in the disappearance of the dome of the observatory. Finally in the 1980s, due to needs of local government outstripping the property, the house was sold and demolished to build new houses. The new neighbourhood is called ''Starfield''.


Description

The observatory was situated in the summit of Crowborough Hill, a hill of roughly 250 m above sea level, the highest point of the surrounding region. The buildings were designed to allow that the telescopes could go down until the 20° above the horizon when they focused above the roofs of the house. Joined to the observatory there were some buildings devoted to a photographic laboratory, with darkroom and facilities for the enhancement of photography. The observatory was connected with the house by a corridor that opened into the library. The
dome A dome () is an architectural element similar to the hollow upper half of a sphere. There is significant overlap with the term cupola, which may also refer to a dome or a structure on top of a dome. The precise definition of a dome has been a m ...
of the observatory was hemispherical, built of wood with copper facing on the outside. There were two apertures of about 120 cm each, closed with doors that split in the middle, the lower half gliding horizontally into the base of the dome and the upper half rotating on the dome.


Instrumentation

In the observatory were housed two telescopes, a
refractor A refracting telescope (also called a refractor) is a type of optical telescope that uses a lens (optics), lens as its objective (optics), objective to form an image (also referred to a dioptrics, dioptric telescope). The refracting telescope d ...
of 7 inches (1787 mm) diameter made by Cooke, purchased by Roberts in 1878; and a 20 inch reflector (100
inch Measuring tape with inches The inch (symbol: in or ″) is a unit of length in the British imperial and the United States customary systems of measurement. It is equal to yard or of a foot. Derived from the Roman uncia ("twelfth") ...
(2,450 mm)
focal distance The focal length of an optical system is a measure of how strongly the system converges or diverges light; it is the inverse of the system's optical power. A positive focal length indicates that a system converges light, while a negative foca ...
), manufactured by Grubb and bought in 1886.''Proceedings of the Royal Society...'', p. 358 Roberts went in contact with the astronomer William Huggins the one who had the mount of the reflector of 20 inches in the axis of declination of the refractor of 7 inches in place of his counterweight. This way both telescopes had independent movement in
declination In astronomy, declination (abbreviated dec; symbol ''δ'') is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle. Declination's angle is measured north or south of the ...
whereas the clockwork mount, which maintained
right ascension Right ascension (abbreviated RA; symbol ) is the angular distance of a particular point measured eastward along the celestial equator from the Sun at the March equinox to the (hour circle of the) point in question above the earth. When paired w ...
, was common for both.James, ''Dr Isaac Roberts...'', p. 120


See also

* Astrophotography


References


Bibliography

* James, Stephen H. G. (June 1996). "Dr Isaac Roberts (1829-1904) and his observatories". ''Journal of the British Astronomical Association'' 103 (3): 120–122. . Consulted on 12 October 2010. * * Roberts, Isaac (January 1891). "Isaac Roberts' New Observatory on Crowborough Hill, Sussex". ''Monthly Notices of the Royal Astronomical Society'' 51: 118. . Consulted on 11 October 2010. * {{DEFAULTSORT:Isaac Roberts' Observatory Astronomical observatories in England Defunct astronomical observatories