NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Double altitude method
From: Frank Reed
Date: 2015 Aug 2, 11:20 -0700
From: Frank Reed
Date: 2015 Aug 2, 11:20 -0700
Jacques,
You are probably already well aware of the paper by Mendoza Rios (1796). It's more famous for lunars math, but the first part, from pages 44 through 76 covers the "problem of Douwes" or latitude by double altitudes:
Even though, you're probably already familiar with this, it's a nice summary, for anyone else interested, of the status of the problem up to that date. The article is in French.
It's interesting, also, that this double altitudes method seems to have been far more important to mathematicians on land than it was to navigators at sea. I have only encountered one single case in a logbook/journal where a navigator indicates that the latitude was found by double altitudes.
Frank Reed
