MASKELYNE, NEVIL (1732-1811, Astronomer Royal and mathematician)
'Greenwich Dec 23. 1783. Sir, I thank you for making me the bearer of your observations of the comet to the Royal Society, which I shall deliver to the secretary immediately. Bad weather and moonlight have prevented my seeing any thing of it. Your observations will be sufficient to settle its orbit, by which it will appear whether there may be any chance of seeing it on the other side of the sun, which I fear there is not. For observing comets when faint & small telescopic stars one must use very thick wires, which will never want illuminating. To my 5 feet equatorial sector I have several plates with wires of different thickness from 1/750th to 1/75th inch, which I apply according to the brightness or faintness of the object, in the focus of the telescope, & never find any difficulty when the object is too faint to admit light being thrown into the telescope. I think the circular field of a transit instrument should have two thick wires put obliquely towards the extremity of the field in the shape of a rhombus, which would not interfere with the other & finer wires commonly used, & would give differences of declination as well of right ascension. I was glad to see two observations of the comet made by Mr Goodric; I understand he has sent further observations of Algel. I am glad he continues his astronomical observations. Be pleased to make my complements to him. I do not approve of the horizontal wire to a transit instrument placed as a diameter of the field....I find two wedges of red & green glasses placed with their refracting angles contrarywise & made to slide over one another is an excellent method of darkening the sun to any degree at pleasure and makes him appear more pleasant and distinct than thro' smoaked glasses...'
Nevil Maskelyne was elected to the Royal Society in 1758 and was sent by it to observe the transit of Venus in 1760, but he was clouded out. In 1765 he was appointed Director of the Greenwich Observatory and Astronomer Royal. For forty-five years he made some 90,000 observations of when the moon crossed the meridian and every ten years the results were published by the Royal Society. He also observed eclipses of Jupiter's satellites, the occultation of stars and planets by the moon, solar and lunar eclipses and the transit of Venus in 1769, and he measured the places of newly discovered bodies, such as Uranus, Ceres, and numerous comets. His greatest contribution to the improvement of navigation and astronomy were his Nautical Almanac and Astronomical Ephemeris and his Tables Requisite. He also worked for many years for the Board of Longitude, regularly assessed the performance of time-keepers and helped to plan the voyages of exploration supported by the Royal Society.
Edward Pigott (1753-1825) and his brother Charles (d. 1845) took the meridian heights of many stars when at Louvain and surveyed the Severn estuary. They built an observatory at York. Most of these letters of Maskelyne are addressed to Edward Pigott in York. In 1783 Pigott discovered the Great Comet and in 1784 detected the variability of Eta Aquilae, the first known representative of a class of variable stars later called Delta Cephei stars. The Asteroid 10220 Pigott is named after Edward Pigott and his father Nathaniel. The Pigotts were related to the Fairfax family.
John Goodricke (1764-1786), a deaf-mute due to scarlet fever in infancy, monitored the variable brightness of the star Algol with Edward Pigott, who allowed Goodricke to be the sole author of a paper read to the Royal Society on 15 May 1783 announcing the discovery -- it earned him the Copley Medal, the Society's highest award. He and Pigott went on to enrich astronomy with a new class of variable stars. He was elected to the Royal Society just two weeks before his death, aged twenty-one years. See Lot 339.