Discovery of Neptune. Diagram published in 1846 showing the discovery of a new planet that would later be named Neptune. The new planet was discovered on 23 September in the constellation of Aquarius (left), near the border with the constellation of Capricornius (right). Saturn is at centre, and the position of the new planet on 23 September and 30 September is shown at upper left. The discovery was made following predictions made by the French astronomer Urbain Le Verrier. This diagram was published in the 10 October 1846 issue of The Illustrated London News, with a letter concerning the discovery by British meteorologist James Glaisher.