who began systematic observations of the positions of the stars, Moon,
and planets at the Royal Observatory he founded at Greenwich, London,
1676. His observations were published in Historia Coelestis Britannica
As the first Astronomer Royal of England, Flamsteed determined the latitude
of Greenwich, the slant of the ecliptic, and the position of the equinox.
He also worked out an ingenious method of observing the absolute right
ascension - a coordinate of the position of a heavenly body - which
removed all errors of parallax, refraction, and latitude. Having obtained
the positions of 40 reference stars, he then went back and computed
positions for the rest of the 3,000 stars in his catalogue.
Flamsteed was born near Derby and studied at Cambridge. He was appointed
astronomer to Charles II 1675, but had to supply his own equipment.
Flamsteed began his astronomical studies at home by observing a solar
eclipse 1662, about which he corresponded with other astronomers. In
1672, he determined the solar parallax from observations of Mars. His
lunar calculations were urgently needed by Isaac Newton and Edmond Halley
to test their theories, but Flamsteed withheld them and fell out with
both in 1704