Petrus Plancius’s celestial globe of 1598
The first detailed knowledge of the far southern stars to reach Europe came from observations made by Pieter Dirkszoon Keyser (c.1540–96) and his fellow navigators on the first Dutch expedition to the East Indies, known as the Eerste Schipvaart. When the fleet returned to the Netherlands in August 1597 these observations were delivered to the cartographer Petrus Plancius (1552–1622), who had asked for them to be made.
Plancius plotted these stars, divided into a dozen new constellations, on a celestial globe that was published by Jodocus Hondius (1563–1612) in 1598 (or late 1597). It was the first all-sky globe ever made. Only one surviving copy of this historic globe is known, in the Historisches Museum Lucerne, and images of it are not online.
However, in 1983 the Dutch cartographic historian Peter van der Krogt discovered a set of 12 globe gores in a volume of cartographic prints held by the Nicolai Collection of the State Library of Württemberg, Stuttgart, which proved to come from the 1598 globe. These uncoloured gores for a globe of diameter 35 cm extend from 70 degrees north to 70 degrees south and include ten of the new southern constellations with their Dutch names. The relevant sections of the five gores containing the new constellations are illustrated at the top of this page. The gores are centred on the ecliptic poles, not the celestial poles, so the new constellations appear on only five of them.
Unfortunately the south polar cap, or calotte, containing Dorado and Volans is missing. Those two figures aside, we can see on these gores ten of the southern dozen constellations – Apus, Chamaeleon, Grus, Hydrus, Indus, Musca (unnamed on the gore), Pavo, Phoenix, Triangulum Australe (unnamed on the gore), and Tucana – as they were first visualized by Plancius. (Being on a globe, they appear reversed from the way we see them in the sky.) In addition, on the leftmost gore above we see Crux, the southern cross (here termed Cruzero), under the body of the Centaur.
The actual inventor of the southern dozen constellations is uncertain, since the original observations were unfortunately never preserved. Keyser himself died while the ships were still in the East Indies and is unlikely to have made much contribution. The 12 new constellations are often attributed to Plancius, but it seems entirely plausible that members of the Eerste Schipvaart would have begun to group the stars into constellations on their way home.
Prominent among these members of the expedition was Frederick de Houtman (1571–1627) who is thought to have contributed to the original observations and who went on to compile a larger catalogue of the southern stars on a later voyage which was published in 1603. He may therefore have played a greater role in shaping the southern constellations than is often recognized.
Plancius himself never published a written description of the new constellations depicted on the 1598 globe but left that to his countryman Paul Merula (1558–1607) in his Cosmographiae Generalis published in 1605.
These new southern constellations first appeared in a printed atlas, as distinct from on globes, on a chart in Johann Bayer’s Uranometria of 1603. Bayer did not have access to the original observations used by Plancius. Instead, as the Dutch historian Elly Dekker has shown, he copied the new constellations from globes by Hondius published in 1600 and 1601, which were modified from Plancius’s 1598 globe.
Acknowledgement: Thanks to Rob van Gent for help with research.
Gores from the Plancius globe of 1598 depicting 10 of the 12 new southern constellations devised from stars recorded by Pieter Dirkszoon Keyser and his fellow navigators on the Eerste Schipvaart in 1595–7. The remaining two new constellations, Dorado and Volans, are on the southern polar calotte, which is missing from the set. Near the bottom of the rightmost gore is the bright star we know as Alpha Eridani or Achernar (here given as Alcarnar), at the far southern end of Eridanus. This was the reference star for the observations, which Keyser and his colleagues measured repeatedly to establish its position with maximum accuracy. These were all naked-eye observations as the invention of the telescope was still over a decade in the future.
(Nicolai Collection of the State Library of Württemberg, Stuttgart)
