NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Sextant precision
From: Alexandre Eremenko
Date: 2004 Sep 29, 16:00 -0500
From: Alexandre Eremenko
Date: 2004 Sep 29, 16:00 -0500
Dear Members, I am answering the questions asked by George (and asking new questions that arise from his letter): On Wed, 29 Sep 2004, George Huxtable wrote: > Alex Eremenko asked about the precision of > sextants and sextant measurements. > This is a matter which surfaces from time to time on Nav-L, I think I read all previous discussions related to sextants, all I could find using the search engine. > I speak, not as an ocean navigator, > but as a small-boat sailor who is never I don't even have a small one:-( Yet. Just chartering. > capable of reading to about 0.1', and > calibrated to a corresponding precision. That's exactly what I am trying to do. > So (for those that don't take lunars) I am planning to take lunars. According to Fred, star-to-star distances is a good preparation for this. > is there any point in using an > instrument capable of measuring to 0.1', for measuring an altitude, No, there is no point. > And yet, on this list, the finer points of calibration > of these expensive > and exotic instruments, ancient and modern, > are discussed in detail, You are not objecting this, do you? > There's another list which is devoted to sextants Could you please give me the address? > possessions to cherish, or even as investments, > rather than as tools to do > a job. Is not GPS a better "tool for the job"? > If Alex is planning to measure lunar distances, Yes, I am planning this too. In general, I am interested in the history of navigation, and history of the instrument making, and history of mathematics and astronomy. > But if he plans to navigate a small boat by measuring > altitudes, then any old sextant will do that job When I navigate a small boat I use GPS. But now I would try my sextant as well (mostly for fun, and for real experience, and to verify various statements on its precision in practical use). > I hope Alex will go ahead with his checks on sextant accuracy, > and inform > us of his results. I will. But I need help from someone more experienced with (metal) sextants. Alex.