Astrology and astronomy
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Astrology and astronomy were archaically treated together, but gradually distinguished through the Late Middle Ages into the Age of Reason. Developments in 17th century philosophy resulted in astrology and astronomy operating as independent pursuits by the 18th century.
Astrologer–astronomer Richard of Wallingford is shown measuring an equatorium with a pair of compasses in this 14th-century work.
An engraving by Albrecht Dürer featuring Mashallah, from the title page of the De scientia motus orbis (Latin version with engraving, 1504). As in many medieval illustrations, the compass here is an icon of religion as well as science, in reference to God as the architect of creation.
Circle
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A circle is a shape consisting of all points in a plane that are at a given distance from a given point, the centre. The distance between any point of the circle and the centre is called the radius.
Circular cave paintings in Santa Barbara County, California
Circles in an old Arabic astronomical drawing.