NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: lunars hard to shoot?
From: Bill Murdoch
Date: 2000 Sep 07, 9:30 PM
From: Bill Murdoch
Date: 2000 Sep 07, 9:30 PM
In a message dated 9/7/00 5:54:42 PM Eastern Daylight Time, george@HUXTABLE.U-NET.COM writes: > Yet in none of these modern texts that I am aware of will you find > any description, or even any mention, of this second sight-line. The current edition of "The Navigator's Newsletter" (issue sixty-eight, summer 2000) has sketches of an octant used for both fore and back sights with both a natural and an artificial horizon. There is a similar drawing in Peter Ifland's "Taking the Stars" on page 89. A friend of mine bought an ebony octant at an auction earlier this summer. It is such a simple thing. Has anyone tried making one himself ? How did it turn out ? The optics are all in the Edmund Scientific catalogue. The ivory scale could be duplicated on an overhead projector acetate with a drafting program and a laser printer. How are sextants checked ? My Freiberger has a table of errors inside the case. How are they determined ? I can imagine measuring the distance between two stars and making the corrections for refraction like a lunar measurement, but I can not reproducibly measure arcs to better than 0.2' holding the sextant in my hand. How could I determine the accuracy of a home made sextant ? Bill Murdoch
