NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Lunar trouble, need help
From: George Huxtable
Date: 2008 Jun 30, 20:20 +0100
From: George Huxtable
Date: 2008 Jun 30, 20:20 +0100
Kent Nordtrom has provided useful comments on his methods, in explaining- "So again, what I have tried to achieve is a re-construction of how the LD�s were measured and reduced in the old days (by Swedish navigators) and not necessarily what will be achieved with todays know-how." Indeed, that explains a lot about the differences between Kent's procedures and my own. His aim, in authentically following the path set by 19th-century Swedish navigators, is of great interest to me, and no doubt to others as well. I wish him success, and hope that he will publish his findings (in English). He adds- "Also keeping the local time with a watch was used but after what I have gathered this was not a common method likely because watches were not good enough. But this method, when working, was certainly much easier for the navigator than the first method outlined by me." Well, there are big differences between the timekeeping standard required from a watch that's expected to keep home-port time over the duration of a voyage (which needs to be some sort of chronometer), and a watch that's just used to relate times of observations, taken within a day or so (a deck-watch). With a deck-watch, you can use a lunar to check its error, and then use that to note a separate time-sight taken at a different time-of-day, so the whole job doesn't have to be done at once. Such deck-watches were available at sea for ordinary mariners, long before chronometers were. There's little to be found, in English-language texts, relating to Swedish ocean navigation. There's a perception, true or false, that in the 19th century the Swedes were great traders with other North-European nations, in timber and minerals, but mainly confined within the Baltic; and that, presumably, wouldn't call for lunar-distance navigation.. That may relate to Sweden's lack of overseas colonies to exploit. Certainly, in the previous century, Sweden, with af Chapman, had been very advanced in ship design, and in Stockholm precise angle-instruments were being made by Ekstrom and others. I hope that Kent can some time tell us a bit more about 19th century marine technology, in Scandinavia. I will address the differences that have shown up, in the detail, between Kent's analysis of Jeremy's lunar, and mine, in another posting. George. contact George Huxtable at george@huxtable.u-net.com 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 -~----------~----~----~----~------~----~------~--~---