Physical description

Bubble Sextant model Mark 1XA type A.M. 6B/218 in protective storage box. Complete, with operation instructions. This is an aviation navigation instrument used by the RAF and RAAF during the World War 2 era.

A sextant is used to measure the altitude of celestial bodies above a horizontal line of reference. A navigator can use the horizon as this line of reference, but when an aircraft is above the clouds or flying at night, the navigator can’t see the horizon. The bubble sextant solves this problem by providing an artificial horizon.

Inscriptions & markings

The storage case has a label with the following: "A.M. 6B/218 MK IX A" and the number "10772/42 (V)"