The manuscript Ambrosiana H 57 sup. includes two texts on the astrolabe, Philoponus’s as well as an anonymous one from perhaps the late 13th century (though this copy is dated 14th century). Along with these texts are a couple Ptolemaic works and Theon of Alexandria’s “Commentarium paruum in Ptolemaei canones.” The manuscript itself is lovely […]
The tradition of planetary hours established a ruling planet for each hour of each day. The first hour of the day was ruled by the planet that also gave the day its name, e.g., the sun ruled the first hour of Sunday. Each subsequent hour was ruled by the next planet in the series: Saturn, […]
Not a day goes by that I don’t miss being able to work in the archives. Travel restrictions that prevent me from going to and working in the archives I need for my research depresses me, to say the least. The fact that there is no end in sight compounds my feelings of loss. There […]
A recent survey of the “Conceptions of Science in Byzantium” opens with a general comment about the term “science”, and by extension the concept “science”. The author roots “science” in the culturally specific values of any given moment, values that are “constantly developing and changing.” These values determine what was and what was not, or […]
Critical editions are incredibly handy. They transform historical artifacts into an easily read, generic version of some text. They smooth out differences between versions, they correct grammar, and they normalize orthography. The labors of intrepid and tireless editors save us untold time and energy. But those same labors, those efforts to efface differences and to […]
In a fragment on the astrolabe attributed to John Kamateros are a handful of interesting diagrams illustrating the various parts of an astrolabe. Here is the diagram showing the rete. There is also diagram illustrating the plate, and two showing different views of the back of the instrument.