Anders Celsius magnitude (a measure of brightness) of certain stars. This was the first attempt to measure the intensity of starlight with a tool other than the human eye. He made observations of eclipses and various astronomical objects and published catalogues of carefully determined magnitudes for some 300 stars using his own photometric system (mean error=0.4 mag). Celsius was the first to perform and publish careful experiments aiming at the definition of an international temperature scale on scientific grounds. In his Swedish paper "Observations of two persistent degrees on a thermometer" he reports on experiments to check that the freezing point is
Charles Green (astronomer) London; the records of the Royal Society mention making a provision of £50 per annum for his wife for the duration of the expedition. Green's sister Mary married the astronomer William Wales, who was part of a Royal Society expedition to Hudson Bay to observe the 1769 transit of Venus and who replaced Green for Cook's next voyage. Charles Green (astronomer) Charles Green (baptised 26 December 1734 – 29 January 1771) was a British astronomer, noted for his assignment by the Royal Society in 1768 to the expedition sent to the Pacific Ocean in order to observe the transit of