Nocturnal, English, late 17th-early 18th century.
© Science Museum / Science & Society Picture Library
Nocturnals were used for telling the time at night from the stars. By the late 17th century, wealthy gentlemen often commisioned highly decorative forms of basic mathematical instruments, using expensive materials, indicating that these objects were designed to impres as well as to educate. Unlike the simplest versions, which could be used only with the 'guide stars' of the Great Bear, more elaborate nocturnals, such as this gilt bras example, could also be used with the Little Bear.