Astronomical Images : Aspects of planets, parallax

Peter Apian

Astronomical Images

<p style='text-align: justify;'>This Venetian edition of Peuerbach's <i>Theoricae novae </i>was copied from Apian's 1528 edition, printed in Ingolstadt. Subsequently, the work went through several further editions. Apian's edition added new woodcuts as well as notations to some of those from earlier editions. Some errors in the woodcuts in the 1528 edition were repeated in this Venetian edition of 1537. The left-hand woodcut shows the various aspects of planets and their symbols. Two planets are in trine when their true places are separated by a third part of the ecliptic; quartile when by the fourth part; sextile when by the sixth part. The right-hand woodcut explains the visible aspects of a star. A true position of a star is the point of the firmament terminating the line from the centre of the World through the centre of the star. The visible or apparent position is determined by the line drawn from the eye (or the surface of Earth) to the centre of the star. The parallax of a star is defined as the arc between the true and apparent positions of the star on the great circle passing through the zenith and true position of the star. MA and CO indicate the parallaxes of the Sun. N, I, L, P indicate the positions of the Moon. The true conjunctions of the Sun and the Moon are indicated by the lines DPC and DNA; the apparent conjunctions by ELHO and EIFM.</p>