Pieter Dirkszoon Keyser (1540 — September 1596), (Latinized in Petrus Theodori ), was a navigator Dutch which charted the southern sky.
After several voyages to the Brazil, Keyser took part as second Master and a navigator chief in the first Dutch forwarding towards the the Eastern Indies (the " Eerste Schipvaart"), which left Texel with four ships the April 2nd 1595. It had been especially pulled by Petrus Plancius to chart southern stars. When the fleet finally managed to get fresh food products with Madagascar on September 13rd, 71 of the 248 sailors had perished, the majority of the Scorbut. The crew surviving remained several months on the island, to take again forces and to make repairs, and Keyser probably made there the majority of its celestial observations. It was helped in this work by Frederick de Houtman and Vechter Willemsz. After having left the island, it took again four months (February in June 1596) so that the ships reach Sumatra and finally Bantam on Java. The trade negociations turned badly, perhaps because of disturbers Portuguese, perhaps by inexperience, the crew was thus forced to find drinking water and food on Sumatra through the Détroit of the Probe, and Keyser probably died at the time of this crossing. The August 14th 1597, 81 survivors regained Texel, of which of Houtman, which probably brought back the observations of Keyser to Plancius.
Keyser and of Houtman are credited for creation with twelve news Constellation S with the southern sky, which was preserved as modern constellations. The majority were named according to the creatures which the explorers of the 16th century had met (for example the bird of paradise, the chameleon, the toucan and the flying fish). They were indicated on the celestial sphere of Plancius at the end of 1597, which was published by Jodocus Hondius. Willem Janszoon Blaeu copied these constellations from a sphere of 1602 and created a new sphere in 1603 starting from the observations made by Frederick de Houtman at the time of a second voyage to the Eastern Indies. Johann Bayer copied the southern constellations starting from a sphere of Plancius/Hondius in its star catalog of 1603 Uranometria, allotting the cartography to a " Petrus Theodori" but not announcing their former publication, and it is thus often credited wrongly to have introduced them.
The Astéroïde (10655) Pietkeyser is named in its honor.
List constellations created
The 12 Constellation S created by Pieter Dirkszoon Keyser and Frederick de Houtman between 1595 and 1597, introduced by Johann Bayer into his work Uranometria of 1603.-
Bird of paradise
- Chameleon
- Sea-bream
- Crane
- male Hydre
- Indian
- Fly
- Peacock
- Phoenix
- southern Triangle
- Toucan
- Flying fish
Sources
- Jim Fuchs' " Filling the Sky" 2003
- Ian Ridpath' S Star Bruise
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