A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Antoine Couëtte
Date: 2020 Mar 11, 12:09 -0700
RE : Using-suns-direct-reflected-image-determine-sextants-IE-TonyOz-mar-2020-g47215
from which clearly follows if we want to know the TRUTH we must do APPARENT + INSTRUMENT ERROR
Not so sure ...
From a recording you either :
- Remove (i.e. "subtract") an error, or
- Perform (i.e. "add") a correction.
PS : To determine Sextant IE, rather than using the Sun which is extremely sensitive to "lateral offset" between both images because of non-zero apparent diameter, much better use a low altitude star : disregard the images offset and when both images are at the same level (do keep your sextant vertical), then you immediately read IE, in a much more expeditious and reliable way, as long as offset is not too big in which case you need to fine-tune your sextant.