A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Ducruy Jacques
Date: 2015 Aug 1, 10:29 -0700
It seems that, during 18e century, the method of double altitude was use only for the latitude : but it is possible to compute also the time ... and the longitude if you have a chronometer.
Cotter tell the first publication on this subject is a little book writed by Owen (1812) : I look for a copy of this book.
I know that this methode was also include in Lynn books ; the french version is due to Pagel (1847). The basis of all these method is the method of Dunn for the calculation of latitude (1776 ?), bhut Pagel used a simplified version due to Ducom (1820).
Thank you very muhch in advance.