Correspondence with R.V. Willstrop at the Siding Spring Observatory. Willstrop's handwritten letters report on commissioning tests, progress and observing, and refer to S.C.G. Gascoigne's accident, a postal strike, encoders for the Northern Hemisphere Observatory, the Koblertron, Hartmann plates, tachometers, dome air temperatures, the Isaac Newton Telescope, I. Arnison, the rumour of O.J. Eggen's resignation, the Royal opening, and the allocation of time on the Anglo-Australian Telescope. Redman reports on the Northern Hemisphere Observatory Planning Committee meetings, Science Research Council news, and progress at Sir Howard Grubb, Parsons and Co. Ltd, and encloses a copy of his handwritten memorandum of 23 April entitled 'Commissioning: Prime Focus'.