A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Bill Ritchie
Date: 2019 Mar 23, 07:06 -0700
Astron V2.1 release.
The lunars section has been extended with much supplementary information. It can be used to calculate time and position from a lunar distance and 2 altitude sights and also, in the reverse direction, to calculate the lunar distance and 2 altitudes for a known time and position. I have also added a rather empirical ‘quality index’ which varies with many factors, including the alignment of the Moon’s motion relative to the other body. I would be delighted to receive feedback on this from some of the regular lunar contributors to NavList.
Astron V2.1 can be run from:-
The extensive User Notes can be downloaded from:-
A brief PowerPoint presentation can be downloaded from
As the subject of Zenith Fixes is current, I have added the original problem as an example in User Notes Chapter 12. The Astron result is S19° 22.36’ E006° 37.57 which is in close agreement with Andres’ result of S19° 22.3 E006° 37.6.
Now back home at 50N 003W.