Astronomical Images : Lunar and solar eclipses

Johannes Sacrobosco

Astronomical Images

<p style='text-align: justify;'>Erhard Ratdolt (1442-1528) was a printer from Augsburg who also worked in Venice for a time. He produced a number of works concerning astronomical and mathematical matters, including an edition of Regiomontanus' <i>Calendarium</i> in 1476 and the first printed edition of Euclid's <i>Elements </i>in 1482. He was also responsible for the <i>Poetica astronomica</i> attributed to G. Julius Hyginus, which dealt with the poetic associations of astronomical bodies and featured lively allegorical representations of the signs of the zodiac. This figure exemplifies the vivacious nature of Ratdolt's images, with the Moon and Sun depicted with animated faces. It is also interesting to note that text and image have been placed on the same page at this early stage in the development of printing. This allowed Ratdolt to illustrate his texts clearly by placing text and image close together. This figure is used to illustrate the difference between the two types of eclipse ' lunar and solar. As the author explains, lunar eclipses occur when, as in the top half of the figure, the Moon passes into the shadow of the Earth, while solar eclipses, shown in the bottom half of the figure, occur when the Moon passes in between the Earth and the Sun and so obscures the light of the Sun. In the case of a lunar eclipse, the Moon takes on a reddish glow, shown here with hatched shading lines (in the absence of coloured ink which might otherwise be applied either during printing or by hand afterwards). The figure does not represent all of the differences between the types of eclipse listed in the text, such as that lunar eclipses are visible from anywhere on Earth, but gives a useful guide to the position of bodies in eclipses.</p>