John Pond

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John Pond (1767—September 7, 1836) was a renowned English astronomer who became the sixth Astronomer Royal, serving from 1811 to 1835.

Pond was born in London and, although the year of his birth is known, the records indicating the day and month have been lost to posterity. Pond's father made a fortune as a London merchant, enabling young John to enter Trinity College, Cambridge at the age of sixteen. He took no degree, however, as his course was being interrupted by severe pulmonary attacks which compelled a long residence abroad.

In 1800 he settled at Westbury near Bristol, and began to determine star-places with a fine altitude and azimuth circle of 2 1/2 feet (750 mm) in diameter by Edward Troughton. His demonstration in 1806 of a change of form in the Greenwich mural quadrant led to the introduction of astronomical circles at the Royal Greenwich Observatory and to his own appointment as its head. He was elected a fellow of the Royal Society on February 26, 1807. That same year he was married and set up residence in London.

In 1811 Pond succeeded Nevil Maskelyne as Astronomer Royal. During an administration of nearly twenty-five years, he effected a reform of practical astronomy in England comparable to that brought about by Friedrich Bessel in Germany. In 1821 he began to employ the method of observation by reflection and in 1825 devised means of combining two mural circles in the determination of the place of a single object, the one serving for direct and the other for reflected vision. Under his auspices the instrumental equipment at Greenwich was completely changed and the number of assistants increased from one to six. The superior accuracy of his determinations was attested by Seth Carlo Chandler's 1894 discussion of them in the course of his researches into the variation of latitude. Between 1810 and 1824 he persistently controverted the reality of Ireland's Astronomer Royal John Brinkley's imaginary star-parallaxes. During the 1829-31 period, he briefly served as Superintendent of the Nautical Almanac. Delicacy of health compelled his retirement in the autumn of 1835.

Among his honors were the Lalande Prize, which was conferred upon him in 1817 by the French Academy of Sciences of which he was a corresponding member and the Copley Medal, presented in 1823. He published eight folio volumes of Greenwich Observations, translated Pierre-Simon Laplace's Système du monde, and contributed thirty-one papers to scientific collections. His 1833 catalogue of 1112 stars was of great value and displayed an accuracy that had previously never been achieved.

As Astronomer Royal, Pond was responsible for a substantial modernisation of the Observatory at Greenwich, extending from improvements to equipment to new working practices. Perhaps his most noticeable addition was the 1833 installation of the time ball on the roof of the Observatory. This—arguably, the first public time signal in the UK—falls daily at 1 p.m. and was intended to help passing mariners on the Thames check their chronometers.

John Pond died in Blackheath, Kent at the age of 68 or 69 and was buried beside and near fellow Astronomers Royal Edmond Halley and Nathaniel Bliss, respectively, in the churchyard of St Margaret's in nearby Lee.