Demonstrate the principal circles of the heavens, in an earth-centred or sun-centred universe
The sphere consists of a spherical framework of rings, centred on Earth or the Sun, that represent lines of celestial longitude and latitude and other astronomically important features, such as the ecliptic. It is believed to have been invented (in Greece) in the 3rd century BCE, and (independently in China) in a basic form in the 4th century BCE developing into the form now known in about the 2nd century CE.
