Sidereal Messenger and Kepler's Dioptrics

PREFATORY NOTE.

About five years ago I was engaged in preparing a catalogue of the ancient books which belong to Christ’s Hospital A historic English charitable school founded in 1552, famous for its "Bluecoat" students.. One portion of these books consisted of a collection of ancient mathematical works presented at various times for the use of that part of the school which is known as the Royal Mathematical Foundation of King Charles II Established in 1673, this foundation was specifically designed to train students in mathematics and navigation for service at sea.. Amongst them were some well known by name to every mathematical student, but which few have ever seen. Perhaps the most interesting of them all was a little volume, printed in London in 1653, containing Gassendi’s Explanation of the Ptolemaic and Copernican Systems of Astronomy Pierre Gassendi was a French priest and scientist who wrote this guide to the competing Earth-centered and Sun-centered models of the universe., as well as that of Tycho Brahe A Danish astronomer whose system attempted a compromise between the Ptolemaic and Copernican models., Galileo’s The Sidereal Messenger original: Sidereus Nuncius; this was Galileo's 1610 report on his first telescopic discoveries., and Kepler’s Dioptrics A foundational text by Johannes Kepler on the optics of lenses and how the telescope works.. I found Galileo’s account