The shadow square, also known as an altitude scale, was an instrument used to determine the linear height of an object, in conjunction with the alidade, for angular observations. It is an early example of an analog computer.[not in citation given] It was invented by Muhammad ibn Mūsā al-Khwārizmī in 9th-century Baghdad.[not in citation given] Shadow squares are often found on the backs of astrolabes.
Here you can share your comments or contribute with more information, content, resources or links about this topic.