NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Accuracy: main shades vs eyepiece shades?
From: Tony Oz
Date: 2019 Jul 25, 01:47 -0700
From: Tony Oz
Date: 2019 Jul 25, 01:47 -0700
Hello!
A spin-off from here: is it methodologically correct to use an eyepiece shade for IE determination - assumed that the main (the index and the horizon) shades are not used in that particular measurement?
My take is - it is not correct to do so, because no matter how good the main shades are, they still have some degree of "prismatic" property. If one does the IE measurement without the main shades - he introduces an unaccounted prismatic error when doing a normal sight (when the main shades are involved). Doing the IE sight through the main shades automagically accounts for "prismaticity" of them.
Please comment.
Regards,
Tony
60°N 30°E
