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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Benefits of Stigmatizing
From: George Huxtable
Date: 2010 Sep 25, 23:59 +0100
From: George Huxtable
Date: 2010 Sep 25, 23:59 +0100
On 22 Sept. I wrote- "I have an English Vernier sextant, around 90 years old, which has in the side of the box a slot containing a little "lens" that can fit over the eyepiece. At a first glance, this looks like simple plain glass, but it has a mark on the rim which is clearly there to show which way up it should go. I have always taken it to be a star astigmitiser, though have never bothered to try it out on a star. If it is, it has a very weak action, because it has no discernable effect on viewing of ordinary objects. Unfortunately, stars here are in short supply at present. Whether my old eyes are good enough to tell the difference is a question." ======================= Tonight, here, is gloriously clear, though a bright Moon in the sky impedes star observation a bit. Jupiter is shining brightly, so I turned the x6 telescope from my old sextant on to Jupiter, with and without that "star astigmatiser", as I took it to be. I couldn't see a ha'porth of difference, with it or without it. So it looks as if it isn't an astigmatiser at all. What is it, then? That's a puzzle. 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.
