Thomas Romney Robinson, the third director of the Observatory, was a well-known astronomer and meteorologist, and besides his commitment to astronomy made experiments in many other fields of science. One of his most enduring legacies is the Robinson Cup-Anemometer, a device for measuring wind speed. The design was originally suggested to him by Richard Lovell Edgeworth, his future father-in-law, and the invention motivated in 1839 by the desire to monitor wind speed and its variability with precision, following the destructive Great Wind of 6 January that year.
An early version of the Robinson Cup-Anemometer was first erected on the roof of the Observatory at least as early as 1845. In 1867, when the Board of Trade decided to establish seven first-class meteorological stations throughout the British Isles, where complete sets of self-recording instruments working by photography would be in action day and night without interruption, it was natural, knowing Robinson's interests in meteorology, for the Armagh Observatory to be selected as one of the stations. From a note in the Observatory Minute Book, the clockwork of the registry of the anemometer had been in action since March 1847, and subsequently from November 1849 every hour for more than 57 years the wind direction and speed were recorded at Armagh. This is a remarkable record, of scientific interest and potential importance for studies of long-term climate change.
The original anemometer was taken down in May 1870 and replaced with the present version, constructed with a cast-iron outer casing, copper cups and rods, and bronze internal fittings. It is this historic instrument which can now be seen at the Observatory and which has been operating (albeit from slightly different locations) ever since. Renovation of the Robinson Cup-Anemometer was completed by Mr Bertie McClure during July 2000, and the instrument reinstalled on the roof of the building in August.