In this month - October
12 October 1915
Scottish born astronomer Robert Innes announced the discovery of the nearest star to our Sun, Proxima Centauri at a distance of approximately 4.24 light years from Earth. It is one of three known stars in the Alpha Centuri system in the constellation of Centaurus. The other two stars being Alpha Centauri A and B. Innes was an amateur astronmer in Australia, identifying double stars, but he is best known for his work in South Africa at the Royal Observatory Cape of Good Hope and in establishing other observatories.
04 October 1957
The first artificial satellite - Sputnik 1 - was launched by the Soviet Union. Weighing 83 kg and 58cm in diameter, it took 96 minutes to orbit the Earth. It fell back to Earth burning up in the atmosphere in January 1958 after completing 1,440 orbits of Earth. The Image of the Soviet postal stamp issued to commemorate Sputnik is courtesy of wikimedia.
31 October 1961
Parkes telescope, fondly named “The Dish”, was officially inaugurated. A 64 metre radio telescope, it is situated 20km north of Parkes in central west NSW. It was used during the Apollo 11 Moon landing to beam the historic pictures around the world. It is one of the largest single dish telescopes in the southern hemisphere.
08 October 1873
Ejnar Hertzsprung. Danish astronomer and chemist. Together with Henry Norris Russell he developed the Hertzsprung-Russell diagram which plots the temperature of stars against their luminosity. Among his other astronomical work, he determined the distances of Cepheid Variable stars.
25 October 1877
Henry Norris Russell. American astronomer. Together with Ejnar Hertzsprung he developed the Hertzsprung-Russell diagram which plots the temperature of stars against their luminosity. Russell spent nearly his entire professional life at Princeton, becoming director of Princeton University Observatory in 1912.
22 October 1905
Karl Jansky (pictured below Credit: NRAO/AUI/NSF). American physicist and radio engineer. First discovered radio waves emanating from the Milky Way. He is considered one of the founding figures in radio astronomy. In honour of his work, the unit used by radio astronomers for the strength of a radio source – the Jansky – is named after him.