Dioptrice / Johannes Kepler, Søren S. Larsen.

Format:

Book

Author/Creator:

Kepler, Johannes, author.

Larsen, Søren S., author.

Language:

English

Subjects (All):

Optics--Early works to 1800.

Optics.

Physical Description:

1 online resource (176 pages) : illustrations

Place of Publication:

Nijmegen : Radboud University Press, 2025.

Summary:

One day in March 1610, the imperial mathematician, Johannes Kepler, received a visitor at his home in Prague. The visitor brought exciting news from Italy, so urgent in fact that he did not even allow himself time to get down from his horse carriage before delivering it: Galileo Galilei had discovered four new planets, using an optical instrument known as the perspicillum, recently invented by spectacle makers in the Netherlands. As Kepler would soon learn, the four new planets were actually satellites of the planet Jupiter, a discovery with profound implications. The Earth was clearly not the centre of movement in the Universe, a fact which provided strong support for the Copernican system with the Sun at the centre of the world.As important as these new discoveries were, however, Galileo provided only a very rudimentary description of the new instrument, the telescope, with which they had been made. Kepler was uniquely qualified to provide a complete optical theory for the instrument. Some years earlier, he had published his first ground-breaking work on Optics, in which he had demonstrated how an inverted image is formed on the retina at the back of the eye, at the focus of the lens. He immediately understood that the geometrical principles, based on which he had developed his theory of optics, could also be applied to the telescope. Over the coming months, Kepler developed the theory of the telescope, explaining not only how the combination of a concave and a convex lens used in the Dutch/Galilean telescope can magnify distant objects, but also showing that the same effect can be achieved with two convex lenses. The latter design, in fact, has several advantages over the Dutch/Galilean variety, and became known as the astronomical or, indeed, the Keplerian telescope. Kepler's theory of the telescope forms the main theme of the Dioptrice. In addition to providing the first theory for the telescope, the Dioptrice also includes a preface in which Kepler gives us a glimpse into the rudimentary state of the field of optics prior to his work. In a commentary on a text by the French mathematician Jean Pena, Kepler discusses such topics as the existence of solid spheres filling the space between the planets, the motion of the Earth, the planets, and comets, evidence of refraction by the atmosphere, and whether vision takes place by intromission or extramission of light rays. He then goes on to discuss Galileo's telescopic discoveries, first those announced by Galileo in his Sidereus Nuncius, and then the subsequent observations of Saturn and the phases of Venus communicated by Galileo in letters transmitted to Kepler by the Tuscan ambassador in Prague. Kepler can hardly hide his excitement when commenting on these discoveries.The Dioptrice is available here in a complete translation into English for the first time. Kepler's text is annotated with numerous notes, referencing Kepler's own letters and other sources. The translation is preceded by an introduction that links the book to Kepler's other work and discusses its conception and impact on the subsequent development of the astronomical telescope.

Notes:

Description based on publisher supplied metadata and other sources.

ISBN:

94-6515-070-3