ALBRECHT Dürer may not be the name most people would think of as producing the earliest printed star charts, but his will be the name that counts when Sotheby's offer a very rare pair of charts in a March 30 print sale.
In fact, the artist and master printmaker was one of a team of three men who produced the first woodcut guides to the night skies of the northern and southern hemispheres in 1515.
The charts, like much of the exceptional work that marks this period of his life in Nuremburg, were produced under the patronage of the Holy Roman Emperor, Maximilian I, and, more significantly, were made in collaboration with the Viennese mathematician, astronomer and cartographer, Johann Stabius, or Stöbern, with whom Dürer had also worked on a woodcut world map in that same year.
Dürer, as the author of two important treatises on art - on mensuration and human proportion - was no stranger to science and mathematics, but it was Stabius who designed the projection seen here.
The celestial equator is shown around the rim of each chart, with the celestial pole at the centre, and as the skies of the southern hemisphere were at this time little charted by Europeans, few constellations are seen in the Southern Sky chart.
Each measuring roughly 18 x 17in (46 x 43cm), the charts are based on the stars of the constellations as catalogued in his Almagest by the Greek astronomer, Ptolemy in the 2nd century AD, and updated to 1500 by the third man to work on the charts, German astronomer Conrad Heinfogel. Radial lines appear at 30° intervals - corresponding to the 12 signs of the zodiac - and a scale around the rim allows the positions of stars to be accurately read off.
In the world map he had worked on with Stabius, Dürer's contribution was principally in the design of the elaborate windheads that surround the Ptolemaic world, and in these two star charts, it is his imaginative, dynamic and influential depictions of the constellations that are the real attraction.
The constellation figures themselves will be reasonably familiar, but in his 'Star Tales' website (www.ianridpath.com/startales) the writer on astronomy, Ian Ridpath, helpfully identifies the figures seen in the corners of the Northern Sky chart - the four authorities of the ancient Mediterranean world on whose descriptions they are based:
At top left is Aratus of Soli in Cilicia, author of the astronomical poem, Phaenomena, while at top right is Ptolemy. At bottom left, we see Marcus Manilius, a Roman astrologer of the 1st century AD and author of a book of constellation lore called Astronomica, and at bottom right, Azophi Arabus, or al-Sufi, the Arab astronomer who revised and updated Ptolemy's Almagest.
In the lower left corner of the Southern Sky chart, Dürer records his own contributions and those of Stabius and Heinfogel by depicting their individual coats of arms, while at top left appear the much larger arms of the Archbishop of Salzburg, Cardinal Matthäus Lang. On the righthand side are dedications to Lang and to Maximilian I.
For those wishing to pursue a much more in-depth discussion of the charts, Ridpath's website also provides a link to The Visualization of Perspective Systems and Iconology in Dürer's Cartographic Works by Adèle Lorraine Wörz.
Clear, strong early impressions with original and vivid colouring, these rare copies of the charts are identified as a first state (of two) of his Map of the Northern Sky and a second state (of four) of the Map of the Southern Sky, but what is more commercially significant is the fact that just ten other examples are now recorded in institutional collections - only two of which show period colour. The charts carry an estimate of £120,000-180,000.
• The world map is even rarer in original form. No 16th century copies are recorded, but in 1781, Adam von Bartsch took pulls from the woodblocks, which still survive in the Albertina in Vienna.