A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Michael Bradley
Date: 2016 Feb 14, 10:56 -0800
Hi again Bill
Re specs this time:
Buy half decent plastic framed reading glasses, keep them in the sextant case.
Wearing the reading specs, adjust the sextant scope focus using the reading glasses so that your overall focus is correct for the infinite focus needed for a sight. Mark the 'joint' infinity focus point on the scope focus adjuster with a tringular slip of stick on mailing label.
Take the sight using the reading glasses and as you take the sextant from your eye afterwards you are immediately focused at reading distance for your timepiece and then sextant scale.
In theory I guess you might run out of scope focus range, but in practice it's worked for my ancient eyes, reading specs, and with both a 6x30mm telescope or a 3.5x40mm conventional scope on my 'heavy' sextant, and also on my 'lightweight' Freiberger yacht sextant with its 2.4 x 25mm telescope. The rubber eye cup on each of the sextant scopes definitely helps to organise the eye and specs into a repeatable position every time.
Michael Bradley 55 North