A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2017 Jul 30, 14:36 -0700
Here's a link to Brad's post about his reflecting circle, which includes within it a link to his detailed presentation (ppt format) about that instrument:
Attached here are two screen captures of two of the slides in that ppt.