NavList:

John, you asked:

"I assume the almanacs have always been subject to fads in the schools
including fads in notation, academic astronomers versus practical
navigators, competition among publishers of almanacs for sales based on
improved ease of use, politics, and so forth. Can anyone share with us
the history of this evolution?"

 

I would say that "fads" per se have been minimal. Navigation was too important to life and wealth to leave much opportunity for fads. As for the differing needs of astronomers and navigators, a simple solution emerged about a hundred years ago in most countries that published almanacs: they published two versions. For example, if you go back to 1920, in the US you would find the "American Nautical Almanac", published for mariners, and the "American Ephemeris and Nautical Almanac", published primarily for astronomers. In the UK you would find the "Nautical Almanac, Abridged for the Use of Seamen" (commonly known as the "Abridged Nautical Almanac" which later became the formal title), designed for mariners, and the "Nautical Almanac and Astronomical Ephemeris" for the astronomers. The terminology was confusing, especially since the astronomers' almanac in the UK was the one usually known informally as THE Nautical Almanac, and only in 1960 were the almanacs for mariners renamed "The Nautical Almanac". This volume resulted from a merger of the publishing operations of the US and UK Nautical Almanac offices. The volumes became identical (but retaining the old titles "American Nautical Almanac" and "Abridged Nautical Almanac" for two years) starting in 1958. The content and layout of the Nautical Almanac has changed only slightly since that date.

 

The transition from RA to GHA occurred around the time of the Second World War, but with varying dates in different countries, some before, some after. GHA was introduced originally to aid in air navigation. Sea-going navigators liked the new calculation style so much that many started carrying around the Air Almanac. This was one period where privately published almanacs managed to get ahead of the game by re-publishing GHA tables in marine almanacs.

 

There's plenty more detail, but I'll stop here for now.