Graphical Construction of an Astrolabe


The planispheric astrolab is based on a stereographic projection of the celestial sphere: circles and angles on the sphere are preserved.

stereographic projection

The initial option of the "Draw" menu is the step by step graphical construction of the plate. Use the "next" button to proceed.
Draw Menu

The menu item "Rete steps" will construct the rete step by step using the "next" button.

"Plate" or "Rete" will draw the complete plate or rete.

"Plate and Rete" is drawing the complete astrolab.

Obliquity of the ecliptic (1000 to 2000),
decreasing by 0.013° per century:
obliquity of ecliptic

Morrison, James E.: The Astrolabe; Janus, Softcover edition, 2007, Rehobot Beach, DE USA;
ISBN-10: 0939320304, ISBN-13: 978-0939320-30-1

Evans, James: The History and Practice of Ancient Astronomy; Oxford University Press, 1998;
pp 141-161.

Oestmann, Günther: Geschichte, Konstruktion und Anwendung des Astrolabiums bei Ziffernblätter astronomischer Uhren; Athena Verlag, Oberhausen 2014, ISBN 978-3-89896-527-9.



Last update: 2023, Oct. 05