NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: ? ? ? Re: SNO-T Sextant
From: Bruce Stark
Date: 2004 Aug 10, 14:27 EDT
From: Bruce Stark
Date: 2004 Aug 10, 14:27 EDT
Courtney,
I wanted an inverting scope partly because the old-timers used them, and because it was Lewis's favorite (Lewis as in Lewis & Clark). I also wanted to be able to measure long lunar distances accurately. An inverting scope has wires in the field of view that help you keep the plane of observation parallel to the plane of the instrument. On page viii of the introduction to my Tables there's a small table showing how important this can be. You'll find similar tables in Bowditch, Raper, and other old manuals.
What threw me off in using the scope was that, with everything inverted, normal reactions had the opposite effect of what was wanted. How would you like to drive through town with a car in which the gear shift was upside-down and backward, and that went left when you turned the wheel to the right?
Learning to use an inverting scope is rather like learning to ride a bicycle. Don't frustrate yourself by working too hard at it. Just give it a try now and then until you get the hang of it and it becomes "instinctive."
Also, be sure to get a rough contact before putting the scope on the sextant.
Bruce
I wanted an inverting scope partly because the old-timers used them, and because it was Lewis's favorite (Lewis as in Lewis & Clark). I also wanted to be able to measure long lunar distances accurately. An inverting scope has wires in the field of view that help you keep the plane of observation parallel to the plane of the instrument. On page viii of the introduction to my Tables there's a small table showing how important this can be. You'll find similar tables in Bowditch, Raper, and other old manuals.
What threw me off in using the scope was that, with everything inverted, normal reactions had the opposite effect of what was wanted. How would you like to drive through town with a car in which the gear shift was upside-down and backward, and that went left when you turned the wheel to the right?
Learning to use an inverting scope is rather like learning to ride a bicycle. Don't frustrate yourself by working too hard at it. Just give it a try now and then until you get the hang of it and it becomes "instinctive."
Also, be sure to get a rough contact before putting the scope on the sextant.
Bruce
