After reading the board for some time, it's time to join in actively.
I decided to teach myself celestial navigation this winter. I've read several books, bought a sextant, nautical almanac, HO 249 sight reduction tables, artificial horizon, and off I went. My first round of sights averaged 5 nautical miles from mile actual position (my backyard).
I have a question that I have been unable get answered and I was wondering if someone could help. HO 249 has three volumes. Volumes II and III are permanent solutions to spherical triangle solutions and do not go out of date. Volume I (the stars) is time sensitive. Are there mathematical corrections to earlier Epochs of Volume I or do they become unusable once the time frame has passed?