A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2018 Apr 6, 11:48 -0700
Ed Popko, you wrote:
"This is a nice set of examples and the first time I had seen a correction factor for the Moon's Oblateness when correcting the moon's apparent to observed altitude (see page 14, step 21). For this lunar observation, the correction is not much and not likely to make any difference to the cleared distant result but since I'm noticing this for the first time, do any other NavList lunarians use this altitude correction?"
No, you've misunderstood. There is no "Moon's Oblateness". That's not a real thing. What he has applied there is a correction for the Earth's oblateness, which slightly changes the Moon's altitude (but not in a way that you can apply directly to clearing lunars, as we have discussed). And this really ought to be obvious to you since we discussed this just recently, and Sean even posted that altitude correction which is taken directly --verbatim-- from the pages of the Nautical Almanac. This is wrong. This is not how you correct a lunar distance for oblateness. It also has nothing to do with the "methods" of DeLambre and Borda.
Quite a few articles on lunars appeared in the late 1990s, and they are nearly all afflicted by a terrible disease: HNS --Hyper-Nerd Syndrome. It's a disease that leads navigation enthusiasts to obsess maniacally over mathematical complexity. If you can make it complex, then you will be rewarded with the admiration of other hyper-nerds, and, who knows, you might even get published in that glorious journal, The Navigator's Newsletter! If there's more arcane math, then that's better for the navigator afflicted by HNS. It creates a barrier of jargon and effort that keeps the riff-raff out. Lunars were converted in that brief era into that nightmare that the critics always claimed they were: a dominion of mathematicians, not navigators.