Numerous mechanical aids to calculation and measurement were being manufactured for astronomical and navigation use. The planisphere was a star chart invented by Abū Rayhān al-Bīrūnī during the early eleventh century.[8] The astrolabe was invented in the Hellenistic environment in both the 1st or 2nd centuries BCE and is commonly https://frankfurt09910.blogrenanda.com/32004633/new-step-by-step-map-for-pc