Tables of the Sun

Simon Newcomb published his theory, known as Tables of the Sun, in 1898. It was used by the American Ephemeris and the Astronomical Almanac into the 1980's to compute the daily positions of the Sun. This Theory is a semi-analytic model which expresses quantities as a trigonometric series with numerical coefficients. This type of model
produces a compact computer function which has enough accuracy to be useful to most users. My goal is to create a model using C which will reproduce exactly the results published in the Astronomical Almanac for the years 1981, 1982 and 1983.