Re: Captain Cook & celestial navigation
From: Frank Reed
Date: 2020 Jan 29, 09:01 -0800
Robin Stuart first read the March issue of Sky & Telescope three weeks ago. Rafael Caruso posted about it last week. I finally got my hands on a copy of the article last night (the nxtbook reader is old-fashioned and insecure, btw).
Robin, you quoted the author:
"For his first voyage Cook used lunar distances as his primary method for determining Greenwich Time. He measured the angular distance between the Moon and the Sun or reference star with a sextant, and recorded the local time. He consulted the British Nautical Almanac to determine at what time the angular distance would be the same if observed from Greenwich."
And then you added:
"And I think he would probably have found it easier just to determine the geocentric angular distance."
I really don't think that's mis-stated in the article, though the prose is a bit murky. Or maybe you were just kidding about the way the author phrased it? I would nitpick over the statement that "mathematicians developed a clever method..." for clearing lunars rather than "a variety of clever methods".
The photo of the "nautical knick-knack" or "fake" sextant is certainly a big thing and disappointing to see, but whatcha gonna do?
As for the "tragic myth about the great man", do you really count Maskelyne as a "great man"? It seems we're in the midst of a reactionary phase.
Setting aside these nitpicks and that unfortunate photo, there's one terrible arithmetic error in the article which someone should have caught. See the attached image from the article. Do the math! I would guess that most NavList readers, even those unfamiliar with lunars specifically, will spot this big mistake.