A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Latitude and Longitude by "Noon Sun"
From: George Huxtable
Date: 2005 Jun 7, 15:09 +0100
From: George Huxtable
Date: 2005 Jun 7, 15:09 +0100
There are some points to pick up from Frank's many recent postings. I had written, about his proposed method for "noon" longitude, which he had said "goes a little beyond the standard procedure for shooting the Noon Sun for latitude only" "It certainly does. It extends the Noon sight to a protracted series of 9 to 13 observations extending over 40 to 60 minutes around noon. Can this still be described as "a noon-sight"? " and he replied- "It can easily be as few as five or six sights." My figure of 9 to 13 observations was deduced directly from his own proposal: for observations every 5 minutes over a period from 20 - 30 minutes before noon to 20 - 30 minutes after noon. I added- "Frank's proposal, though the best way to do the job of finding longitude around noon, is quite a protracted operation. On how many lightly crewed small craft can a crew member be spared for a period of 40 to 60 minutes around noon each day while he takes such a series of shots at 5-minute intervals?" to which came the reply- "No, it is NOT a protracted operation." Indeed it is. "Protracted" means "drawn out in time", which it certainly is, at 40 to 60 minutes, when compared with the usual noon-sight for latitude. Frank added- "There is no requirement that the sights be taken every 5 minutes like clockwork. Every "five or ten" as time (and interest!) permit... " But that doesn't alter the protraction. As for the suggestion that someone has to give up 40 or 60 >minutes of their day, gimme a break. It takes about a minute to take and >record each sight. You could easily make --and eat-- lunch during that time >taking a break every five or ten minutes for a quick sun sight. Well, if I had a crew member would be devoting the next 40 - 60 minutes to such closely-spaced observations as Frank has suggested, I wouldn't expect much useful boatwork out of him in the 2 or 3 minute free intervals in between. In reply to my- "There may be some interesting implications in what Frank is saying here. With this method, he is teaching a way of finding lat and long that is only available if the Sun happens to shine around the moment of noon. That's the position navigators were in prior to Sumner, when if they lost their noon (or near-noon) observation, both lat and long were unavailable until the >next sunny noon." this from Frank- "First, this is inaccurate historically. Sumner's discovery was considered an>"exotic" sight method for decades. It was rarely used in practice." Even if that was the case (and he has provided no evidence for that sweeping statement), in what way would it make my previous sentence "inaccurate historically"? he continued- "...Well into the twentieth century, many vessels were navigated by traditional noon latitude and afternoon/morning time sight." That may be. So what? Frank- "But back to your main point -- yes, of course, this method is limited to those days when it is clear or partly cloudy around noon. But so what? Celestial navigation is NOT a primary method of navigation any longer." It seems to me, then, that a teaching programme, confined to around-noon Sun observations and no others, will produce pseudo-navigators who may delude themselves into thinking that they can determine lat and long from celestial observations, but are in fact only safe on a vessel that is actually being navigated by GPS. What would be the name of such a course? If some sort of certificate is provided as a result, how would it be worded? Would it form a required part of any other qualification? Referring to position-line navigation, I added- "If all that has been lost (and I hope it hasn't), it would be a very crippled 19th-century navigator that would emerge from the course." Frank- "Just to be clear,the method I have described for getting lat and lon by noon sun was NOT used in the 19th century. It is a modern method." Well, noon by equal-altitudes has been around since long before the 19th century, but primarily for on-land use as it was regarded as insufficiently accurate at sea. What's so specially new that makes Frank's a "modern method? Frank- "Short, easy to teach, easy to learn, easy to RE-learn in one sitting, and requiring no special tables beyond four or five pages of basic almanac data which would be valid for decades. It is not a cheat. It is not "fake" celestial navigation. It does have some limitations, as do all methods of celestial navigation. As for your use of the words "crippled" and "poor" and so on, your are engaging in shameless exaggerration." A phrase Frank used in another posting, "instant gratification", describes what is being offered, perfectly. I don't think I used the word "fake", but perhaps "facile" would be more appropriate. If without GPS, then I would prefer to be guided by a navigator trained in the 19th century, rather than by a product of Frank's proposed class. If navigating by GPS, NEITHER is needed. I don't withdraw my description of the man emerging from Frank's proposed class as a "crippled" navigator. Indeed, I wonder if he will even be aware of what it is he is missing. Finally, may I say that an important aspect of position-line navigation, to me and perhaps to others, is its universal application, together with its basic simplicity, and indeed, its intellectual beauty. True, in applying it, there's a lot of hard graft with tables, which can be bypassed with a pocket calculator if preferred. Nothing that's worthwhile comes easy. George. ================================================================ contact George Huxtable by email at email@example.com, by phone at 01865 820222 (from outside UK, +44 1865 820222), or by mail at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK. ================================================================