"Eye witness account of the Great comet of 1680, also known as Newton's Comet: first comet discovered by telescope. One of the brightest comets of the 17th century, it first appeared on 14 November and was last seen 19 March following. It was used by Isaac Newton to test and verify Kepler's laws and gave rise to one of the earliest European scientific publications issued in the New World (Kino's "Exposisión). Our anonymous observer describes the comet's location, course and size, compares them to earlier comets and proposes explanations in accordance with various authorities (Copernicus, Riccioli, Brahe, the Paris Jesuits, Kepler...). He then pivots to the upcoming conjuntion of Saturn, Jupiter and Mars in 1682." -- booksellers summary.