| | The Saphea Arzachelis |
 | | In order to overcome these shortcomings, Gemma Frisius designed an instrument that had an ordinary astrolabe on one side and adopted a form of astrolabe that can be used at any latitude for the other side and included a magnetic compass in the throne. |
 | | As Henri Michel put it, "The "Astrolabum Catholicum" was definitely not Gemma Frisius' invention and, with the typical lack of concern of the time, the learned cosmographer 'forgot' to say that this instrument had been contrived five centuries earlier". |
 | | Gemma Frisius was a professor of medicine in Louvain who apparently became interested in astronomy and astronomical instruments through the astrological aspects of medicine as it was practiced at that time. |
| www.astrolabes.org /SAPHEA.HTM (2124 words) |