A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Greg Rudzinski
Date: 2020 Mar 9, 10:21 -0700
The Bowditch glossary staes index correction as the correction due to index error and index error as difference between arc scale zero (micrometer reading ?) and index mark zero. I interpret this as minutes off or on arc as index error and index correction as the value to apply to the observed reading on the micrometer drum.