<p style='text-align: justify;'>This Parisian edition was copied from the first edition of the commentary of Peuerbach by Erasmus Reinhold, printed in Wittenberg by Hans Lufft in 1542. Subsequently, in 1556, Charles Perier published a new edition, copied from the revised edition printed by Lufft in 1553, which contained additions to the theory of the Sun (<i>[Theoricae] auctae novis scholiis in theoria Solis ab ipso autore</i>). This diagram is an improved version of a traditional figure. The original edition of Peuerbach (c. 1474) and the Fine edition (Paris, 1525) contained a first version of it, with only one epicycle drawn. The Apian edition (Ingolstadt, 1528) and the Wittenberg edition (1535) represented a second epicycle. In the 1551 Wittenberg edition of the <i>Theoricae novae</i>, this Reinhold diagram has been introduced. The diagram shows the position of the ascending and descending nodes, the Head and Tail of the lunar Dragon. Peuerbach explains that the plane of the eccentric of the Moon intersects the plane of the ecliptic, as the axis of the orbs that carry the lunar apogee intersects the axis of the ecliptic at the centre of the World. Thus, the line of intersection is a diameter of the World. One part of the plane of the eccentric declines from the plane of the ecliptic towards the north, the other towards the south. The Head and Tail of the lunar Dragon are situated at the points where the eccentric circle intersects the plane of the ecliptic. The Head, or ascending node, is at the point where the centre of the epicycle 'begins to go northward' (<i>versus Aquilonem incipit ire</i>): when the centre of the epicycle passes by this intersection, carried along by the movement of the eccentric deferent, it enters the half of its path that declines northwards. For the descending node, or Tail of the Dragon, it is the reverse. These intersections are not immobile; they move each day westward about three minutes more than the diurnal movement, as they are carried along by the fourth orb of the Moon, called the 'deferent of the Head of the Dragon'. The mean motion of the Head of the Dragon (<i>medius motus Capitis Draconis</i>) is the arc, measured westward (<i>contra successionem</i>) on the ecliptic, from the beginning of Aries to the line drawn from the centre of the World passing through the Head of the Dragon. The true motion of the Head (<i>verus motus Capitis</i>) is the arc of the ecliptic from the beginning of Aries to the same line passing through the Head, but measured eastward (<i>secundum successionem Signorum</i>). The same measurements can be made for the Tail. Of course, if we add the mean and true motions of the Head, the sum is 360 degrees, and 'by subtracting the mean longitude of the Head from twelve Signs [= 360 degrees], its true longitude is the remainder. And thus the common maxim, that the Head of the Moon goes as much with the mean motion against the firmament as in reality it goes with the firmament, is understood to mean that the mean longitude of the Head of the Moon extends westward to the point to which the true longitude extends eastward' (<i>Ex his manifestum est, quod subtracto medio motu Capitis a duodecim Signis, verus eius motus remanet. Unde commune dictum dicens, Caput Lunae tantum medio motu ire contra firmamentum quantum in veritate vadat um firmamento, ita intelligitur medius motus Capitis Lunae contra successionem Signorum in eum punctum protenditur, in quem verus secundum successionem Signorum</i>). Peuerbach later explains, in the middle section of the treatise (<i>Passiones planetarum</i>), that solar and lunar eclipses occur only when the Sun and the Moon are near the nodes, either at New Moon or at Full Moon. In the diagram, the outermost circle is a zodiacal limb partially graduated (Aquarius, Pisces and Aries are visible, graduated from ten to ten degrees). Inside, the two intersecting circles are the eccentric deferent (LHMN) and a circle in the plane of the ecliptic (GHKN). In the legend, Reinhold calls the former 'the Moon's way' (<i>via Lunaris</i>), and the latter 'the Sun's way' (<i>via Solaris</i>). L marks the point where the eccentric has its maximal northward declination from the ecliptic, as it approaches our zenith (<i>L punctum maxime declinans in Boream ab ecliptica, tamquam vicinius nostro vertici</i>). M marks the point where the eccentric has its maximal southward declination from the ecliptic, and is at its remotest position to our zenith (<i>M punctum maxime deflectans in Austrum, et remotiss[imum] a nostro vertici</i>). The symbol of the 'Head of the Dragon' (<i>Caput Draconis</i>), or ascending node, with the belly [<i>venter</i>] of the curve upwards, is at point N, near the right intersection, and the symbol of the 'Tail of the Dragon' (<i>Cauda Draconis</i>), or descending node, with the belly downwards, is at point H, near the left intersection. Both intersections are, of course, diametrically opposed and situated on the line of intersection between the two planes. The epicycle in also represented with the Moon in two different positions: when its centre is at L, at its maximal declination northwards; and at M, at its maximal declination southwards. A is the beginning of Aries. The radius that defines the 'true position of the Head' (<i>verus locus Capitis</i>) is line TNE, extended from the centre of the World to the zodiac and passing through the ascending node. Arc AE measures the 'mean motion or longitude of the Head' (<i>medius motus Capitis</i>), reckoned against the sequence of the Signs. Arc ABCDE measures the 'true motion or longitude of the Head' (<i>verus locus Capitis</i>), reckoned eastward. Translated quotations of Peuerbach's <i>Theoricae</i> are from Aiton (1987). Quotations from Reinhold's commentary are translated or paraphrased by Isabelle Pantin.</p>
