Telescope, Sighting, No 9 Mk III

No 9 Mk III Telescope made from brass tubing and fittings with multiple coated glass lenses in tube. The eyepiece is offset at 45 degrees. The focus ring has a variable magnification ring up to 16 power magnification. The tube is coloured gloss black with the markings 'CSO AUSTRALIA TELESCOPE SIGHTING NO 9 MARK III'.

Telescopic sighting instrument used by long range heavy artillery units of the Australian Army and Navy during the Second World War for coastal defence installations and anti -aircraft guns. It was manufactured at the Commonwealth Solar Observatory (CSO) on Mount Stromlo, Canberra. A small observatory was established on Mount Stromlo in 1911, becoming the CSO in 1924.

In July 1940, at the suggestion of the observatory's director Dr Richard Woolley, the observatory ceased almost all peacetime activities and devoted its resources to making optical munitions. The Munitions Annexe made prisms and optical lenses, and all the grinding and polishing machines used were designed in the observatory and made either in its own workshop or in a workshop in Canberra. By the end of the war, the observatory ranked alongside the University of Melbourne as a centre for pioneering optical techniques and for disseminating them into industry.

The principles of operation of the Telescope, Sighting, No 9 is fully described on p189 of the 'Addendum to Handbook of artillery Instruments 1914 HMSO, London.