NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: The development of bubble sextants
From: Douglas Denny
Date: 2009 Aug 18, 04:56 -0700
From: Douglas Denny
Date: 2009 Aug 18, 04:56 -0700
Agreed. Brain not in gear. Coriolis is relevant when own local inertial frame is moving relative to moving Earth's inertial frame. I am too sloppy in my fast writing of these things without thinking. ------------- PIM is affected by rotating Earth inertail frame relative to the "fixed" gyro axis and suitable restoring feedback. All this is getting too esoteric and far far away from the point I made however - that horizontal accelerations cannot be eliminated unless there is some time-integrating reference to the local geopotential force. That is exactly what the clockwork averaging mechanism does on the MkIX BM sextant; or in a more crude fashion, with the median averaging method on some WW2 bubble sextants. It is also exactly what is done with the early type of air-operated artificial horizons in aircraft. Douglas Denny. Chichester. England. --~--~---------~--~----~------------~-------~--~----~ NavList message boards: www.fer3.com/arc Or post by email to: NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---
