NavList:

David C, you wrote:
"In 1935 S M Burton published A Manual of Modern Navigation."

I have a copy of the second edition of that, written/updated in 1941 and the printing date is 1943. In it he talks about the slow transition from the methods of the Old Navigation to the methods of the New Navigation. That's how these methodologies were named in the US at least, and in parallel with Burton, you can read Mixter's Primer of Navigation from the same period which says almost the same thing with similar expressions of frustration. These books were part of a building wave of "propaganda" trying so very hard to persuade the old-school navigators to get with the program.

You wrote that in
"1955 he published  The Art of Astronomical Navigation. IMHO the latter is important because it was published near the end of the CN era and before the introduction of the HP35."

I really think this is the wrong way to characterize things. First, 1955 was in no sense a date "near the end of the CN era". I consider 1958 to be one of the peaks of celestial navigation. The modern "Nautical Almanac" was published in nearly its final modern form (though with different titles) for the first time in 1958. In the US the best mid-twentieth century edition of "The American Practical Navigator" (or "Bowditch") was published by the USN/USHO in 1958. Celestial was in its prime in 1958!

Also, you mentioned the HP35. I would say that the introduction of the HP35 and other electronic calculators in the 1970s didn't spell a further end of celestial navigation. They enhanced it. They made the calculations easier, yes, and many navigators eagerly applied them to the work. But most navigators were still suspicious of calculators due their (perceived) high rate of failure and because they were powered by fallible batteries. Celestial navigation remained in active use on vessels of many sizes through the 1980s and beyond.

You wrote, quoting/paraphrasing Burton:
"In his preface to The Art of Astronomical Navigation Burton wrote (abridged by me):
This book first appeared in 1935 its purpose then being to hasten what seemed the overslow conversion of Merchant Navy navigators from older methods to position line methods. That conversion may now be thought of as complete."

That makes sense. I've seen similar comments from other authors in this period, and I'll take them at their word in the absence of contradicting primary source evidence (which I think is unlikely). By 1955 only a small minority of navigators were still practicing the Old Navigation. The intercept method, aided by modern short tables, had won its converts. There seems little doubt that the mass education of new navigators during the war years had a significant impact.

You concluded:
"Either Burton was setting out the state of CN in 1955 or he was defining what he thought it should be."

Some of each, I would think. His earlier book, also a slim volume, is not encylopedic. He's not laying out all the methods that exist. He's trying to provide recommended methods. It's a textbook manual with an efficient, practical goal and preferential approaches to the problems at hand.

Please let us know if you find any other interesting tidbits in it. Burton wrote clearly and carefully spelled out the limits and proper application of the techniques he described. He was also pleasantly "conversational" in his approach to the issues. In the 1941/43 copy that I have of his earlier Manual of Modern Navigation, there's an appendix where he responds to a complaint about the Moon being useless for navigation since it moves too quickly. He counters this and uses that story as an invitation to "come over bag and baggage" to the "camp" of the "New Navigation". Join us. We have hats! ...is rather what he's saying.

Frank Reed