Antique Octant by Thompson, Yarmouth.
A superb early 19th Century antique navigator’s Octant engraved THOMPSON, YARMOUTH. - The early features found on this Octant probably date it from 1810 to 1820. - Simon Thompson is recorded as working from two addresses in Yarmouth from 1805 to 1844.
On the front of the Octant there is a double peep hole fore sight pinnula, to be used in conjunction with the fore sight horizon mirror. This Octant is also fitted with a back sight peep hole pinnula and back sight mirror. ( the back sight was used to measure angles greater than 90 degrees ) There is also a set of three brass framed coloured glass sun filters that are interchangeable between the index mirror and the horizon mirror.