A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Position-Finding
From: David Pike
Date: 2017 Sep 14, 00:00 -0700
The human computers working in England were busy bees in the year 1767 and after, and it wasn't long before they were five years ahead of the calendar. It's a bit of a puzzle that you can't buy a modern Nautical Almanac for a year five years ahead of the calendar today.
Perhaps it was to do with the length of time before you could next visit a decent book shop. E.g. Cook’s voyages from August 1768 3 years, 3 years, and 4 years. DaveP