NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Modris Fersters
Date: 2025 Aug 1, 07:20 -0700
David,
You wrote:
"Unfortunately, GHA Aries, if my memory serves me correctly, isn’t the same for the same time and day from one year to the next. You must wait four years for them to be the same".
You are right. The GHA Aries changes from year to year. And every 4 years (in leap years) there is a jump in its value. But these differencies in the worst case do not reach a full degree even during 20 year period. (I am attaching GHA Aries values in 03.07. UT=00h during 20 year period. Leap years are filled grey.)
In Frank’s puzzle I don’t expect accuracy of minutes of arc. Plus minus degree or some degrees would be a good result. Therefore uncertainty of GHA Aries in my opinion is not an issue.
Sorry, I don’t understand your concept of 3 other possible positions. At given date and time the particular star arrangement in the sky can be sean only from one specific location. Therefore even one star map is enough to determin the location.
Modris
