Quite a few mechanical aids to calculation and measurement ended up created for astronomical and navigation use. The planisphere was a star chart invented by Abū Rayhān al-Bīrūnī inside the early eleventh century.[eight] The astrolabe was invented within the Hellenistic world in both the 1st or 2nd centuries BCE and https://in99763.ltfblog.com/25829465/everything-about-für