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    Re: Haversines with Logarithms
    From: Frank Reed
    Date: 2020 Oct 23, 00:36 -0700

    Gary, you wrote:
    "Almost right Frank"

    I can't tell what you're referring to here, Gary.

    But I'm glad to see you have posted images from the 1937 edition of the "American Nautical Almanac" that I sent to you! :) We can see Fritz Keator's signature on the cover --he was the first director of the Seaport Planetarium, now Treworgy Planetarium, at Mystic Seaport Museum. Don Treworgy, before he passed away in 2009, could talk about "Professor Keator" endlessly... 

    The "American Nautical Almanac" was one of four official almanacs that are either genuine nautical almanacs or might potentially be confused with a nautical almanac. The other three are "The American Ephemeris and Nautical Almanac" which was the US astronomers' almanac, despite the word "nautical" in the title, and "The Nautical Almanac" (sometimes "...and Astronomical Ephermis") which was the UK astronomers' almanac, despite that big bold "Nautical" right there in the title, and finally "The Abridged Nautical Almanac" or (inside title) "The Nautical Almanac Abridged for the Use of Seamen" which was the closest UK equivalent to "The American Nautical Almanac". These latter two were the slim, paper-bound volumes that eventually merged in 1958 and were re-titled two years later that became the modern "Nautical Almanac". Indeed, if you pick up a Nautical Almanac (that merged volume) from 1958 or later, its primary pages are barely distinguishable from the Nautical Almanac for the year 2020. And of course in later years we have various "air almanacs", too.

    Key point here: in the first half of the 20th century there were four official english-language nautical almanacs, so-called, and only the cheap paperbacks known as the "American Nautical Almanac" and the "Abridged Nautical Almanac" were important to mariners, and they were significantly different from each other. I consider this a good thing. They created a competitive intellectual "marketplace' for navigational ephemeris data. 

    In addition to the official nautical almanacs, there were commercial versions which usually included ephemeris pages that were directly licensed from the official "Abridged Nautical Almanac" but also sometimes included other resources. The most famous and long-lasting example was Reed's Nautical Almanac (no connection my name, btw). Brown's Nautical Almanac was also popular. In the US before the mid-1850s there were multiple re-prints like Blunt's Nautical Almanac and Megarey's Nautical Almanac. Some of these included additional content, but mostly they were unlicensed copies of the official, British Nautical Almanac back then. 

    Here's a fairly detailed chronology of the nautical almanacs that I put together some few years ago: Nautical-Almanac-history.pdf. This is almost entirely a library history, a bibliography, with no underlying human history to it.

    Frank Reed

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