Essential information

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Included in venue ticket
Royal Observatory, Meridian Line and Historic Royal Observatory, Time & Longitude gallery, Flamsteed House

Ever seen naval officers in movies looking through one of these? Find out why.

A sextant is used to measure the angle between two objects. At sea this might be the angle between the horizon and a known object in the sky to help you know where you are.

This elegant sextant has a polished brass diamond-pattern frame with a protective frame over the fittings and mounts, and a wooden handle.

The telescope is 119 mm in length with an inverted image. An extra drawtube for the telescope measures 68 mm, with an inverted image and four cross wires. A second extra drawtube is 64 mm with an erect image and a rotating variable shaded eyepiece with of four shades, one clear and three red.

The sextant is contained in a shaped fitted wooden box, containing a trade label in the lid for J.W. Norie and Co, Leadenhall Street, London (1812-39) and illegible pencil notes dated June 1835. The instrument has a polished brass limb with inlaid silver scale from -2° to 135° by 15 arcminutes, measuring to 121°.