NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Riddle of the Secant
From: Jacquelin Hardy
Date: 2026 Aug 12, 14:12 -0700
From: Jacquelin Hardy
Date: 2026 Aug 12, 14:12 -0700
Airmen use the Magnetic North , with magnetic compass, even today, I believe.
And they have to adjust their directional gyro every 15 min. or so
Since the early 1900's, seamen have used True North, with a North seeking gyroscope.
No adjustment for precession needed.This is why it is important to check the compass, sometimes.
These gyros turn at speeds up to 20,000 rpm, depending on the brand , Anschutz, Sperry,Tokyo Keiki...It's a good idea to check them once in a while
