A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Greg Rudzinski
Date: 2016 Apr 2, 11:28 -0700
Performance conclusions of the Davis MK 3 sextant:
1. Lack of a scope limits use to bright stars, planets, Moon, and Sun.
2. Only a 2' vernier scale precision on the index arm.
3. Horizon mirror has no means to adjust out side error. The fixed horizon mirror side error requires making a correction table through the arc.
4. Index error must be checked before and after each observation.
In spite of the above instrument limitations it is still possible to obtain +/- 3' accuracy which makes this ($40 new) plastic sextant a good value for small craft cruiser looking to back-up the GPS. The next post will review the Ebbco Special which is the next step in plastic sextants for the value navigator.