THEODOLITES

The surveyor’s tool of trade. We used Tavistok and Wilde T2 Theodolites. Essentially they measured horizontal and vertical angles. The angles were expressed in degrees, minutes and seconds. Our observed round of angles had to close within a tolerance of 10 seconds. We recorded our round of angles on prepared booking sheets. Tropical humidity could be very unkind to the theodolites

STEEL TAPE

A robust measuring tape that had little stretch over distance.

TELLUROMETERS

These were microwave distance measuring systems using the speed of radio waves between a master and remote unit. Readings were taken from the master unit’s cathode ray tube display. A thin fluorescent broken donut shape gave different readings on a number of switched phases. These readings were placed on our booking sheets where a distance could be calculated through set procedure and formulae. Power to the unit was supplied by a 12V car battery. Tropical humidity played havoc with these units.

Bdr P S Hopper operating a MRA 3, with back removed to lessen condensation.
Operaion Santa Fe.
Photo courtesy P S Hopper.

CURTA

A mechanical calculator similar in size to a 200g jar of Vegemite. A small stepped drum where numbers could be set around the side while others were “stepped” by shifting the lid into notched positions and “ground” out with the small handle. After calculating, the answer would be displayed on the lid.

MAGNETIC COMPASS

Always accompanied us as a rough check to all the bearings observed or calculated. On occasions when Survey transfer was held up through difficult terraine, resection & intersection with compass bearing, provided temporary workable coordinates.

Photo courtesy J McFadden.

BANDEROLE POLE & PIN

Thin pole hammered into the ground to which a coloured pin is pressed into the top. They marked temporary stations in a traverse.