My colleague Ken using a Tellurometer for survey work on Mt Lacey, in the Prince Charles Mountains. Obsolete now due to satellites and GPS, back in 1966 the Tellurometers were the best way to measure distance between two points. With two on separate mountains firing a microwave beam to each other, it was possible to measure distances to within a few centimeters. When this was taken, we were in contact with a surveying field party further to the south. Temperatures were about -12 C at this stage.