A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Antoine Couëtte
Date: 2016 Aug 25, 08:02 -0700
Hello to all,
In a recent "Capella - Betelgeuse - Canopus" post I was sharing the fact that Capella, Betelgeuse and Canopus were looking almost on the same great circle as seen from the naked eye. Subsequent computation showed that the "middle star" Betelgeuse is not closer than 3.1° from the Capella - Canopus great circle, a somewhat disappointing result.
This morning, in exactly similar conditions, i.e. coming to Darwin N.T. Australia from the west after a long night flight ... I also noticed that Aldebaran, Rigel and Canopus (again) were pretty much on the same great circle. Computation shows that the "middle star" Rigel lies at 2.3° from the Aldebaran Canopus great circle: a little better than the previous example.
Our undisputed winner so far remains the prestigious "Canopus - Achernar - Fomalhaut" triplet which is almost perfect to the naked eye. These stars are almost equally spaced and Achernar lies just 1 degree off the Canopus - Fomalhaut great circle.
So Canopus is the end star of 3 sets of first magnitude stars almost lined up to the naked eye: Canopus-Betelgeuse-Capella, Canopus-Rigel-Aldebaran, and Canopus-Achernar-Fomalhaut.
To our equatorial and southern hemisphere readers, enjoy !