Several mechanical aids to calculation and measurement have been made for astronomical and navigation use. The planisphere was a star chart invented by Abū Rayhān al-Bīrūnī from the early 11th century.[eight] The astrolabe was invented within the Hellenistic world in possibly the 1st or 2nd generations BCE and is frequently https://michaelw233dwo6.wikiusnews.com/user