Updated: Mar 8
Cooke Troughton & Simms Tavistock
This is the instrument on which Len performed the observations necessary for the majority of his desert work; the box wrapped in thick sponge rubber and flannelette to protect it while Len in his trusty Land Rover negotiated the rough conditions. It was used for astro-fixes and ground surveys for the laying out of trig stations, instruments and infrastructure for the Woomera Rocket Range, Emu & Maralinga and Giles Weather Station plus of course the road network. It was returned to him from W.R.E. just prior to his retirement in 1988 and he was very happy to have it back!
Astronomical Observations (astro-fixes)
Connie has described the theodolite and its functions in a bit more detail in the video below and also on their Beadell Tours website,
www.beadelltours.com.au/surveying, including a brief outline on latitude & longitude. Essentially for astro-fixes the angles read from the theodolite were used to calculate mean results for latitude and longitude using a nautical almanac and time signals in the case of longitude; the calculations included adjustments for celestial refraction, parallax (for sun latitudes) and many other things. More pairs of stars were read for a more accurate result. It was a very complex field!
Connie Beadell shows us Len's theodolite
(be kind, I am not a surveyor.....)