A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: David Pike
Date: 2019 Mar 13, 16:56 -0700
Brad you wrote:
It’s easy to get confused; well it is for me. Stop thinking about it for a moment, and come at it from a different angle.
Ignore the equation of time for the moment.
I live at 53N.
Where does the Sun rise? A. Roughly in the East. So what’s its azimuth? A. roughly 090.
When is the Suns azimuth to me really close to 090? A. . It has to be otherwise it can’t be azimuth 180 to me at
What’s the definition of my prime vertical? A. A great circle going through my zenith and points on my east and west horizon. Therefore the Sun has to cross my prime vertical when its azimuth to me is 090 (by definition).
At the equinoxes the Sun will cross my prime vertical at my horizon at roughly and for all sensible latitudes (check the daily pages for around 21st March and 23rd September). In the summer, it’ll be higher at and , but it’ll always be at azimuth 090 and 270 to me. DaveP