NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Off Center Sextant Scope Observations
From: Fred Hebard
Date: 2007 Nov 26, 17:19 -0500
From: Fred Hebard
Date: 2007 Nov 26, 17:19 -0500
I'll take a look George. On Nov 24, 2007, at 5:14 PM, George Huxtable wrote: > > Fred Hebard wrote- > > | As I recall when determining index error using the sun, the point of > | contact varies with up and down location in the telescope. > > ================== > > Response from George. > > How interesting! When Fred says "As I recall ...", is he going just > by a dim > recollection, or is it a real, reproducible effect, that he can see > whenever > he tries to repeat it? To me, it appears to defeat the laws of > optics as I > understand them, but that doesn't lead me to deny that Fred saw > what he saw. > It makes it worth examining more closely to discover why. Could > it result, > perhaps, from a mirror that wasn't exactly flat, so the reflection > angle > varies slightly when you use a different part? Or a shade with a > bit of > ripple in it? Tell us more, Fred. > > 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. > > > > --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to NavList@fer3.com To , send email to NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---