NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Randall Morrow
Date: 2013 Apr 23, 07:55 -0700
Thank you for your feedback. Here is what I use:
1) 5x or better magnification?
7 power prism scope
2) a properly adjusted, good-quality, metal sextant?
Astra IIIB newer model with larger rectangular index mirror
3) carefully measured index error?
Regular index correction checks using the sun. I usually do 8 measurements and check by using the listed SD for the sun that day.
(On + Off/4= SD value) I use the value that fits this best.
4) no significant arc error?
Unkown
I am always seated for observations, in a chair that allows me to slouch back and get head and neck support.
It is difficult to keep the bodies in the center of the field of view, which seems to affect masurements.
I have checked and corrected side error and mirror perpedicularity error.
There is no adjustment of collomation error on an Astra.
I have moved the telescope a bit laterally to increase viewing area.
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