A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: John D. Howard
Date: 2020 Mar 3, 05:11 -0800
I do not think he saying west of the sub-point. I think he was saying that GHA is the same as a west longitude. Going west from Greenwitch GHA and longitude are the same but past 180 D. the GHA continue to 360 D. but longitude becomes east ie. a 270 D. GHA is a 270 west longitude or to us, a 90 D. east longitude.
John H. 41 N 100 W