Celestial navigation glossary
Zenith distance (z)
90° minus the altitude: the angle from straight overhead, and the distance to the GP.
Where the course teaches it
Working a noon sight, in the module Latitude from the noon Sun. Know when noon is by your watch, and work a complete noon sight for your latitude.
Taught alongside it
- Local apparent noon (LAN)
- The moment the Sun crosses your meridian and reaches its highest altitude of the day.