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Re: Lunar distances - shot clearance methods
From: Frank Reed CT
Date: 2004 Sep 20, 23:06 EDT
From: Frank Reed CT
Date: 2004 Sep 20, 23:06 EDT
(Revisiting a post from a week ago)
George H wrote:
"As I see it, however, Arnold's method, including standard refraction and
parallax in his tables I, II, and III, was inflexible in that it would have
been unable to adapt to such requirements."
Another thought on this:
The biggest issue with lunars was the first hurdle: getting people to try them at all. And that means that efficient tabular methods that had no complicated "cases" to learn were likelier to succeed in the navigatonal marketplace. I've recently been looking over Thomson's Lunar tables (included in Bowditch for most of the 19th century), and, like Arnold's and many others, they have no provision for including non-standard refraction (temperature and pressure variations) and only a primitive capability with respect to solar and planetary parallax. That's apparently why Thomson included a second method in his original tables. It's there for perfection-seeking navigators who wanted to throw in every last little detail. His standard method, sleek and refined as it was, produced results quickly and without a lot of fuss, and that's probably why it was popular.
Frank R
[ ] Mystic, Connecticut
[X] Chicago, Illinois
George H wrote:
"As I see it, however, Arnold's method, including standard refraction and
parallax in his tables I, II, and III, was inflexible in that it would have
been unable to adapt to such requirements."
Another thought on this:
The biggest issue with lunars was the first hurdle: getting people to try them at all. And that means that efficient tabular methods that had no complicated "cases" to learn were likelier to succeed in the navigatonal marketplace. I've recently been looking over Thomson's Lunar tables (included in Bowditch for most of the 19th century), and, like Arnold's and many others, they have no provision for including non-standard refraction (temperature and pressure variations) and only a primitive capability with respect to solar and planetary parallax. That's apparently why Thomson included a second method in his original tables. It's there for perfection-seeking navigators who wanted to throw in every last little detail. His standard method, sleek and refined as it was, produced results quickly and without a lot of fuss, and that's probably why it was popular.
Frank R
[ ] Mystic, Connecticut
[X] Chicago, Illinois