Sextant

The expedition on which this sextant was used was the first to be successful in attempting to cross Australia from the south to the north and return. The Union Jack was hoisted at Charles Creek, Van Diemen's Gulf, on July 25 1862 and the party returned to Adelaide on 21 January 1863. Sextants replaced the octants as the prefered navigational device in the late eigtheenth century when greater accuracy in measuring angles was required. 'Sextant' refers to the arc of the instrument, which is 1/6 of a circle. The sextant was developed for navigational use but it became a more precise instrument which could be used anywhere.