A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Sean C
Date: 2015 Oct 10, 21:48 -0700
No, I don't wear glasses/contacts. Unlike the rest of my family, I've been blessed with naturally good vision. [Knocks on wood.] Although, it has been a while since I've had it checked. Maybe I should do that.
I'm not sure I understand your recommendation of "panning", entirely. Do you mean moving the sextant in such a way as to cause the reflected image to appear to move from one side of the horizon glass to the other? If so, I don't think that's my problem. I found that, unlike using the 3.5X scope, the division between the mirrored and clear portions of the glass was plainly obvious. I dare say too much so. I had to keep the two images of the sun (remember I was using an A.H.) just to one side of the line so that the protective layer behind the silvering didn't obscure the point of contact. I did experience another sort of strange phenomenon, though. If I looked through the sight tube for an extended period without blinking or looking away from the sun, I found my vision would "wash out" (for lack of a better term). It was the same kind of effect one sees when staring at a printed word for too long. It seems to almost disappear. I don't recall this ever happening when using the 3.5X scope.
I should probably also mention that I had one side of the glass off of my A.H. I still have a problem with it fogging badly when the water starts to warm in the sunlight. And there was a slight breeze that day, causing the reflected image of the sun in the A.H. to distort. I don't know if the water was ever completely still. That may have contributed in large part to my errors. I did find it slightly easier doing index error checks...although, as I said, I still got widely varying results from those. I think a lot more practice is in order before I can really nail down any problems, or their causes.