John Flamsteed (1646 – 1719) was an English astronomer, who was the first Astronomer Royal (granted the title 'The King's Astronomical Observator' from 1675 to his death), and oversaw the establishment of the Royal Observatory (the Royal Greenwich Observatory located on the River Thames and the Greenwich meridian, 0˚ East.)
Flamsteed made many accurate astronomical observations, including data that were used by Isaac Newton in his work – Newton having obtained the data through underhand means and even arranged publication of some without consent.
Flamsteed contributed to the ongoing debate about the nature of comets (denying a common view they move in straight lines, for example) and his work may well have influenced Newton's developing thinking about gravitation.
Flamsteed had intended to enter the service of the Church and was ordained a deacon (who would assist a parish priest) and expected to be taking up a 'living' in such a role, before he was invited to undertake observational work for a Royal Commission. Later, in 1684, he became a priest and took up a role as a rector of a parish alongside his astronomical duties.
Over the period 1681-1684 Flamsteed gave a series of lectures at Gresham College, which were published (in 1975!) and so provide a record of the state of astronomical ideas and knowledge at that time.
