A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Peter Fogg
Date: 2010 Nov 26, 18:58 +1100
To make a long story short, after personnally using the painstaking "manual slope plotting" method up until the early 80's, with the arrival of "smart" calculators - I chose the HP41 family then - I have (successfully I think) attempted to avoid manual plotting while still remaining (sufficiently I hope) cautious about outliers.
With plentiful computing power all the sights can be reduced, thus multiple sights of each body observed, and the software can work out a fix. I have an electronic nav calculator that does this. But for manual sight reduction I prefer to evaluate raw sights first via the slope technique to reduce random observational error before sight reduction. Any systemic error is resolved later.
Regarding Manual Plotting, and with the exception of any obvious "flashing outlier" which you are expected to detect and remove anyway, I have often noticed - thanks to GPS - that what might apparently look as an 'outlier' may not always be one actually and that discarting it at this early stage might not always be the best course of action.
I now simply use plain averaging
How does this averaging work in practice, given you're dealing with different times and altitudes? How do you go about averaging them?
Finally Antoine, you're always so exquisitely polite that you've inspired me to have a go:
Je vous prie d’agréer, Monsieur, l'expression de mes salutations distinguées.