NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Lat/Lon by "Noon Sun" & The Noon Fix PROVE IT
From: Hewitt Schlereth
Date: 2009 Apr 23, 17:59 -0400
From: Hewitt Schlereth
Date: 2009 Apr 23, 17:59 -0400
George, I have a Mac iBook and it doesn't have a spread-sheet program. Pressing F9 does absolutely nothing. The AppleWorks program did open your "long around noon.xls" attachment. What I was presented with looked much like a ledger page. The altitudes I used for figuring longitude were from the "perturbed alt" row on that page. They were nearly equal - i.e.,10.812 at 1210, 10.815 at 1250. The altitude for latitude was from the same "perturbed alt" row - 10.914 at 1230. Hewitt On 4/23/09, George Huxtablewrote: > Hewitt Schlereth wrote- > > > | George, it looks like I may have misunderstood the document I got the > | (nearly) equal AM/PM altitudes from. I thought it was your spreadsheet > | and cited it's designation - LONG AROUND NOON.XLS (SS) - in the > | worksheet I attached to my e-mail. The numbers I used were from that > | document - which I took to be yours. They looked mighty like sextant > | altitudes; so, certainly not random numbers generated by me. > | > | Maybe my worksheet didn't come through to the List? Here it is again. > > ================== > > > Hewitt and I have got ourselves at cross-purposes, it seems. > > I had produced 20 simulated sets of "perturbed" sextant altitudes, each of > 13 observations taken at regular intervals around noon. These were offered > so that list-members could analyse them in any way they chose, to try to > discover the original latitudes and longitudes on which they were based, > information which I withheld. The table was attached to [7940] as > > noon1a.rtf, or (the same data), attached to [7959], as noon1a.doc . > > > In case anyone wanted to see how that data had been generated, I also added > the Excel spreadsheet, that generated those data sets.. Each time that > spreadsheet is run, (or when button F9 is pressed), a new set of random > numbers is generated, which creates a new, unique set of perturbed > altitudes. I hadn't intended anyone to use that spreadsheet itself to > generate those sets of altitudes, but there's nothing wrong with doing so; > indeed, that's what Dave Walden did, generating 1000 such sets to look for > the scatter. > > Hewitt has done the same, but has generated only one such data-set, which > has given an answer which Hewitt tells is is within 1' of the intial value. > To which I suggest that if that is the case, it's only so as the result of a > fluke, and will not be repeatable. > > If Hewitt will kindly load and run that Excel program again, it will invent, > this time, a completely new set of 13 altitudes, showing a similar general > shape but differing in every detail. And if he analyses the new set as he > did before, he will, I suggest, get a very different answer. Every time he > presses F9, it will change again. > > However, having satisfied himself on that score, he could usefully apply > whatever technique he chooses, to one or more of the data sets attached to > those messages cited above, also attached here. The first two sets, only, > provide that original data. For the other 18, only I know the original lat > and long from which the data set has been constructed. > > > George. > > contact George Huxtable, at george@hux.me.uk > or at +44 1865 820222 (from UK, 01865 820222) > or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK. > > > > > --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---