when was neptune discovered

Neptune was discovered on September 23, 1846. It was the second planet to be found using a telescope. The discovery was made by astronomer Johann Gottfried Galle, who observed it at the Berlin Observatory based on mathematical predictions of its position by Urbain Le Verrier. Although it had been observed previously without recognition, credit for the discovery is given to Le Verrier and John Couch Adams, who predicted its existence through calculations. Neptune is too faint to be seen with the naked eye, which is why its discovery was reliant on telescopic observations and mathematical prediction.