NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Transcription of Worsley's Log
From: George Huxtable
Date: 2009 Mar 22, 10:02 -0000
From: George Huxtable
Date: 2009 Mar 22, 10:02 -0000
Thanks to Henry for posting his confirmation of Worsley's calculation of chronometer error, on departure from Elephant Island. He wrote- "My analysis is based on an assumption that his DLo of 1 minute + 4 seconds is to be read as time units as opposed to arc." That's surely correct. What Henry requires is a definitive map of Elephant Island. I have unearthed a map of Elephant Island, made by a UK joint services expedition in 1970, which must be about as precise as it's possible to get. It'a a fold-out from the Geographical Journal, September 1972, part of a paper by the team leader, Malcolm Burley. That survey is probably the basis for the British Antarctic Survey data that Henry has mentioned. I will send a scan, covering the relevant part of the island, directly to Henry, and to anyone else who asks, rather than publishing such copyright stuff to the list. I will add a couple of pages of description of the location of Wild camp, as found in 1970, which includes an amusing account of the conflicts between the hard-bitten military team and the local wildlife for occupation of the limited space available. And a page from the diary of Orde-Lees, one of those who had to await Shackleton's return to Elephant Island. That Burley map allows the true location of Worsley's observation spot, in latitude and longitude, to be rather precisely located. As I've written in earlier mailings, the latitude is important, as Worsley wasn't able to make a noon observation to measure it, so had to assume the best figure he could find, presumably from a chart. With that new data, latitude as well as longitude, we can reassess Worsley's estimate of chronometer error, based as it was on inaccurate information, of position of a somewhat different spot from the actual observation site. Armed with that information, I invite Henry to recalculate Worsley's chronometer error, to check Brad's calculations, of what Worsley would have made that error to be if he had known, then, as much about the local geography as we know, now. Henry wrote, in his attachment- "Regardless, because of a simple lack of concrete information, assumptions have to be made in assessing Worsley's calculations or the whole quest given up. Anybody's guess is probably as good as mine. He, however, is said to have been a good navigator and it seems hardly likely that he would have made as serious an error as has been otherwise postulated." Nobody is postulating any error in Worsley's work. Indeed, we have found it to be a textbook example of precision in the most difficult circumstances. The difference we have deduced from his own assessment of chronometer error (of no more than a minute-and-a-bit, in time) is due to inaccuracies in the geographical data available to him, which in the circumstances he could do nothing about. 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 -~----------~----~----~----~------~----~------~--~---