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
Christian Mayer (astronomer) able to continue his astronomical observations and studies. He applied for and was granted in December 1765 a Fellowship of the Royal Society. He is most noted for pioneering the study of binary stars, although his equipment was ill-suitable for distinguishing between true binaries and coincident star alignments. In 1777-78 he compiled a catalog of 80 double stars, which he published in 1781. During his lifetime he became a member of numerous learned societies. He died in Heidelberg. Christian Mayer (astronomer) Christian Mayer (August 20, 1719 – April 16, 1783) was a Czech-German Catholic priest, astronomer and teacher. He was