NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Antoine Couëtte
Date: 2019 May 14, 21:12 -0700
Helllo to all,
Deneb, Altair and Saturn look approximately lined up and equidistant to northern observers in the morning skys nowadays.
It would be interesting to determine from a geocentric perspective the date and time when they are [almost] exactly lined up and their angular separations then.
Trial and error can solve the problem.
One way of proceeding involves a change of equatorial coordinates reference axes for all Celestial Bodies in which Deneb and Altair "pseudo Declination" becomes zero. When Saturn "pseudo Declination" becomes also zero in such coordinates system, then all bodies are all aligned, and their geocentric angular distances can be determined though subtracting their "pseudo Right Ascensions".
Any taker here ?
Antoine Couette
