Bubble sextant with a clockwork averaging mechanism, an R.A.F. pattern

Bubble sextant, mark IX B, in a transit case

Bubble sextant, mark IX B, in a transit case

Bubble sextant, mark IX A, in a fibre case marked '304 R. Sadonski'

Royal Air Force bubble sextant, MK iXA, c. 1950s

Bubble sextant comprising of a black crackle-lacquered alloy casing incorporating artificial materials, housing optical equipment, a clockwork averaging mechanism, electrical equipment, and a rubber eyecup, in a fitted aluminium case, signed by Henry Hughs & Son Ltd, London, c. 1940

Bubble sextant, Air Ministry Mark IXA, Stores Ref No 6B/218, Serial No 3760/42