NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Dipmeter: was [NAV-L] Wires, back sights and collimation
From: Alexandre Eremenko
Date: 2004 Dec 1, 19:01 -0500
From: Alexandre Eremenko
Date: 2004 Dec 1, 19:01 -0500
And another related question: On Wed, 1 Dec 2004, Frank Reed wrote: > why do they never fix the > mirrors rigidly on a sextant, > Presumably because the mirrors have to be re-silvered now and then. The older sextants apparently had collimation adjustment. The newer do not. One can argue that this is because with modern technology they can make sure that the telescope mounting is rigid enough... But then another interesting question SNO-T is produced with two telescopes: 7x30 inverting (Kepler) with wires, and 4x50 upright (Galileo) like on most modern sextants. The inverting one has collimation adjustment while the upright one has none. The mountings are of course absolutely similar. Why? Is this related somehow with higher magnification of the inverting scope? But then why the 6x or 7x prismatic scopes of modern sextants don't have it? Alex.
