Royal Observatory, Greenwich

Bradley (1693-1762) was the third Astronomer Royal, in office 1742-1762. Bradley entered Balliol College, Oxford, in 1711 and graduated B.A. in 1714 and M. A. in 1717. Under the influence of his uncle, James Pound, he showed great aptitude for observational astronomy early in life. By the time that he was appointed to be Halley's successor at Greenwich, his scientific reputation was established; today we recognize his rigorous demonstration of the aberration of starlight in 1729 to be of fundamental importance. Further observations made in this investigation lead him to note what he suspected was the nutation of the Earth's polar axis caused by the gravitational attraction of the Moon on a slightly asymmetric Earth, an effect predicted by Isaac Newton, though Bradley resolved to make observations of the effect throughout the 18.6 year cycle of the nodes of the Moon's orbit before conclusively showing the cause and effect. It was Halley himself who recommended that Bradley succeed him as Astronomer Royal, indeed offering to resign in the latter's favour, through in the event Halley died in office. As his predecessor had, Bradley managed to persuade the government of the day that the Greenwich Observatory should have new instruments and with these he carried out stellar observations of unprecedcented accuracy, pursuant to the expressed intent of the original warrant founding the Observatory that the stars should be newly obs

erved for the purpose of finding the longitude. Towards the end of his life, in 1758 Bradley observed the return of the comet predicted by his scientific patron Edmond Halley, and though ill health prevented him from participating, he was instrumental in arranging for observations of the transit of Venus of 1761 to be made at wide geographical separations, again as Halley had suggested.

Pond (1767-1836) was sixth Astronomer Royal; in office 1811-1835. Though he studied chemistry at Trinity College, Cambridge, ill health forced Pond to leave the university before graduating. He returned to England in 1798 after an extended European tour and set up a Troughton altazimuth telescope in Somerset, an instrument with which he was able to demonstrate the deterioration of the Bird quadrant at Greenwich. Becoming a Fellow of the Royal Society in 1807, he moved to London and became involved in the construction of astronomical instruments. Nevil Maskelyne recommended that Pond should be his successor as Astronomer Royal and Pond was thus appointed after Maskelyne's death in 1811. Pond modernized the instruments of the Greenwich Observatory and introduced more rigorous methods of observation and reduction. Pond was a founder member of the Astronomical Society in 1820 (later to become the Royal Astronomical Society). In 1820 the Admiralty took over control of the Observatory from the Board of Ordnance, the latter body having overseen its work since its foundation in 1675, when Jonas Moore was Surveyor of the Ordanance and John Flamsteed's patron. The change of control, though logical given the nautical reasons for the Observatory's work, lead to a great increase in the amount of work undertaken at Greenwich, this being largely due to the testing of many marine chronometers for the Royal Navy which the Admiralty insiste.

D should be done there. Though the number of assistants grew, for the first time since 1675, Pond was not well served by them, the work of the Observtory generally suffered and the reliability of the 'Nautical Almanac' deteriorated. Pond was the first Astronomer Royal to retire from his office, rather than to die in harness, and his 24 year tenure is sometimes thought to be the least successful of the Astronomers Royal as Directors of the Royal Observatory. John Pond was nevertheless a peerless practical observing astronomer who introduced new instruments, observational and reductional methods to the Observatory; in many ways he laid the foundations for the work of his successor, G.B. Airy.