NavList:

Dustin Baenen, you wrote:
"It would be interesting to find out when Weems added the letter and why he chose to do so. "

Yes, I agree. It's always critical to work within contemporary thinking and assumptions. Aerial celestial navigation in the 1930s was evolving rapidly. Arguably, it was the center of a revolution in celestial navigation generally. Practices that we see as standard and obvious in any decade since the middle of the 20th century may have seemed exotic in 1937. 

The tools of celestial navigation were also undergoing rapid changes in this period. For example, Gary has pointed out that the author of that flimsy "dateline theory" based her thinking on R.A. or "right ascension" instead of GHA (and SHA). He suggested that this implied she was approaching the topic from an astronomer's point of view. That's quite possible, but bear in mind that GHA as a tabulated parameter in the almanacs was brand new. The concept had been around for decades, and navigators had often calculated values of GHA (though often expressed in hours and minutes, not degrees) from other quantities as part of their work, but our modern standard of tables of GHA and Dec and little else did not yet exist. Parallel listings of GHA alongside the old standard of RA (or the Equation of Time for the Sun) began in the American Nautical Almanac only in 1934 (experiments in earlier years). That's new! Certainly Noonan was plenty smart enough and experienced enough to understand tabulated GHA and see its merits, but you have to step back in time. The American Nautical Almanac for 1937, the year of Earhart's doomed flight, was only the fourth annual edition that featured this new GHA listing. What we see as normal and obvious today was radical and unusual back then.

You might also wonder why they didn't just use The Nautical Almanac. I've said it before, but it bears repeating: The Nautical Almanac in the 1930s was the equivalent of the modern Astronomical Almanac. It was a reference for astronomers in observatories. 

Personally, I see these attempts at fiddling with the navigation practices of Noonan and Earhart, as in the "dateline theory", as grasping at straws. They're unprovable, and they reflect the simple fact that we have no real evidence to work with. The aircraft vanished in the middle of an enormous ocean while still marginally in radio contact. Unfortunately that was not a rare event back then. More important than actual geography was the social geography. This famous pioneer of aviation, this exceptional woman intriguing to her public, didn't disappear in the Pacific Ocean; she disappeared on the front pages of newspapers all across America.

Then again, maybe it was alien abduction, and we'll find Fred and Amelia one day in the Delta Quadrant.

Frank Reed