Nevil Maskelyne(1732-1811), Astronomer Royal
Sitter in 4 portraits
In 1761, Maskelyne travelled to St Helena to observe the transit of Venus, using observations from this expedition to illustrate The British Mariner's Guide (1763). The guide gave instructions for finding longitude at sea by lunar distance. Maskelyne then travelled to Barbados on behalf of the Board of Longitude to test a rival source of longitude, a new watch invented by John Harrison. He was appointed Astronomer Royal on his return. Maskelyne's greatest achievement is the annual Nautical Almanac and Astronomical Ephemeris for which he was responsible for almost fifty years. The Almanac is the reason the international systems of time and longitude are today based upon the Greenwich meridian.