Neptune

Neptune was discovered in September, 1846, by Johann Galle in Berlin, Germany, on the first night of his search for a trans-Uranian planet which had produced previously unexplained perturbations of Uranus's orbit. These prompted Urbain Leverrier in France to calculate the predicted position of this undiscovered planet; he sent his calculations to Galle, who then discovered Neptune. However, there is evidence that Galileo Galilei had earlier fortuitously observed Neptune near Jupiter on December 28, 1612, and January 28, 1613, and J. Lalande also had observed it in 1795, but neither astronomer recognized Neptune as a trans-Saturnian (Uranian) planet. Lassell discovered Neptune's largest satellite Triton several weeks later in 1846.