NavList:

Dale Lichtblau, you wrote:
"Kudos to Worsley are hardly exaggerated."

Sorry, but I don't agree. He has become an object of affection, an icon of the polar explorer-hero with a dash of geeky "engineer salt" on top. He is no longer a historical human being.

You added:
"He got them to South Georgia, I seem to remember."

They reached South Georgia. Yes, miraculously, they did, albeit not where they hoped to be. Did Worsley get them there? There was very little real navigation on that voyage (by the position-finding definition). Certainly it was an excellent example of the seamanship definition of navigation, but otherwise, in terms of latitude and longitude, it was largely educated guesswork. The very few Sun sights taken by Worsley were analyzed in the most ordinary fashion (which any ocean navigator in the era, even one with minimal education, would have understood and recognized as "ordinary" too). Those sights contributed modestly to the process of reaching South Georgia, but they were not critical. So very many people who have heard or read the story fill it out with their imaginations.

Dale L., you concluded:
"Robin Stuart, Lars Bergman, et al., know the story. Look it up."

Heh. Yes.

I've been trying to compose a description of my contract work for Expedition22 without making too much of it and without stepping on anyone else's toes. The appropriate catch-all name for the job is probably "analyst" but a title that also would apply is "translator". I was paid (several times in piece-work contracts) in the past year to analyze and translate everything that Robin and Lars et al. wrote up in scholarly articles about Worsley's navigation. I distilled their papers to recover the specific aspects that might be important to the location of the wreck at the bottom of the Weddell Sea. I was also paid to identify errors (very few), omissions, alternative perspectives, and perhaps most importantly, I was paid to provide independent analyses.

I remember several years ago, Robin Stuart did a presentation at a small "lunars" workshop/seminar that I had organzed at Mystic Seaport Museum (August 2019, I think it was), and he took us through the basic analysis of those occultations from 1915. It was a facinating presentation. Back then and again last month, when I was asked to review the pre-print of the occultations paper, I wondered why they had not done a complete modern analysis of the occultations (if my memory serves, when I asked Robin in 2019, it was simply that they were done with the project "for now"). Lunar occultations in the modern world are a "solved problem", and if any of you would like to explore them further, from the perspective of amateur astronomy, I suggest visiting the IOTA website. If you're a Windows user (or you're comfortable with a Windows emulator), you might try installing the "Occult" software tool that has been created for amateur observers. When I call occultations a "solved problem" I should add that I'm referring specifically to the historical case of "occultation timing" (that's the OT in IOTA) for stars passing behind the lunar limb. That limb is not smooth. Empirical limb models have been available since the 1960s, but it's only within the past twenty years that the final element became available: spacecraft-derived DEMs (digital elevation models) of the Moon's surface. The mountains and depressions of the lunar surface have been mapped to high accuracy, and they have a substantial impact on the timing of occultations. The lunar limb varies as a function of the (topocentric) lunar libration angles. This was largely an unsolvable problem a hundred years ago. For them the effect of the lumpy lunar limb was simply "noise" in the observations.

Frank Reed
Clockwork Mapping / ReedNavigation.com
Conanicut Island USA