Ernest William Brown
Ernest William Brown FRS (29 November 1866 – 22 July 1938) was an English mathematician and astronomer, who spent the majority of his career working in the United States and became a naturalised American citizen in 1923.[1][2]
Ernest William Brown
22 July 1938 (aged 71)
Royal Medal (1914)
James Craig Watson Medal (1937)
Fellow of the Royal Society (1897)
His life's work was the study of the Moon's motion (lunar theory) and the compilation of extremely accurate lunar tables. He also studied the motion of the planets and calculated the orbits of Trojan asteroids.
Legacy[edit]
Brown's Tables were adopted by nearly all of the national ephemerides in 1923 for their calculations of the Moon's position, and continued to be used with some modification until 1983. With the advent of digital computers, Brown's original trigonometrical expressions, given in the introduction to his 1919 tables (and from which the tables had been compiled), began to be used for direct computation instead of the tables themselves. This also gained some improvement in precision, since the tables had embodied some minor approximations, in a trade-off between accuracy and the amount of labour needed for computations in those days of manual calculation.[13]
By the middle of the 20th century, the difference between Universal and Ephemeris Time had been recognised and evaluated, and the troublesome empirical terms were removed.[13] Further adjustments to Brown's theory were then made, arising from improved observational values of the fundamental astronomical constants used in the theory, and from re-working Brown's original analytical expansions to gain more precise versions of the coefficients used in the theory.[14]
Eventually, in 1984, Brown's work was replaced by results gained from more modern observational data (including data from lunar laser ranging) and altogether new computational methods for calculating the Moon's ephemeris.[15]