On the evening of 23 September 1846, Johann G. Galle of the Urania Observatory in Berlin saw the planet Neptune within 1° of where Urbain Le Verrier and John Couch Adams predicted it would be. Tomorrow night, it will have been exactly one Neptune year since the discovery, according to Sky and Telescope. However, I’m not entirely sure their maths is correct. My own calculations show that the big day will not be until next week, while Wolfram Alpha says that it was yesterday. Obviously only one of us can be right. If you would like to give it a try, why not drop me a line at [email protected] and let me know who you agree with?