1) Arab invention 2) Astronomical instrument
Found on
https://www.crosswordclues.com/clue/equatorium
An equatorium (plural, equatoria) is an astronomical calculating instrument. It can be used for finding the positions of the Moon, Sun, and planets without calculation, using a geometrical model to represent the position of a given celestial body. The earliest extant record of a solar equatorium, that is, one to find the position of the sun, is fo...
Found on
http://en.wikipedia.org/wiki/Equatorium
computational instrument for planetary astronomy
Found on
http://phrontistery.info/e.html
No exact match found.
