NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Shane M
Date: 2026 Apr 13, 07:42 -0700
Gentlemen,
Thank you for the replies. I infer from both of them that you usually use the NA's tabulated value and do not routinely measure horizon dip.
Gary: I haven't used a bubble sextant in some years but I shall give it a try.
Frank: I understand what you mean about the "confetti". I reckon that same blurring of the horizon equally affects measurements of dip and of altitude. It also seems on par with the effects of actual waves viewed on the horizon and changes in dip due to the heave of the vessel (i.e., momentary changes in height of eye). So I don't suppose it is possible (or necessary) to measure dip much closer than the 1/2 to 1 arcminute of precision but if a multi-minute error can be easily measured then it seems worth the effort.
I shall keep you posted if I make any progress along this line.
