Abu Mūsā Jābir ibn Hayyān often known simply as Geber(c.721–c.815) was a prominent polymath: a chemist and alchemist, astronomer and astrologer, engineer, geographer, philosopher, physicist, and pharmacist and physician.
Astronomicum Caesareum Michael Ostendorfer. 1520-1549. Renaissance instructive manual explaining the use of the astrolabe (for calculating the altitude of stars) and other instruments used for computing planetary positions. The author, court astronomer to Emperor Charles V, also provided new observations on the comet of 1531 (Halley's Comet).