A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Robin Jouan
Date: 2017 Sep 24, 02:58 -0700
Hello Ron and Antoine,
My first answer was using GHA and Dec as given by Ron. And the result was on the target (as Peter Hakel did it).
If I use integrated ephemerids of ASTROLAB to compute GHA and Dec of Deneb, Pollux, Spica, I obtain through ASTROLAB total automation:
48° 7.8' N & 123° 27.7' W, which is 1.28 NM in 242° from my first result. DOP is obviously similar, but standard deviation is near 2 NM.
Adding Arcturus (4 body problem) slightly changes this location into 48° 7.7' N & 123° 25,7' W, with reduced standard deviation.
I will comment these figures, if needed.