NavList:

Bruce,

I get 1' accuracy or better with all three of my metal sextants using a water pool shielded from the wind. Artificial horizons are more accurate because there is no doubt about height of eye (zero), perpendicularity , or horizon quality. On a ship it is another story where 2' accuracy is good. On a sailboat 3' accuracy is good.

I just did some trials with a framed mirror floating in a pan as seen in the attached picture. The Sun's image was steady but accuracy was between 5' toward and 20' away (mirror reversed). I will be attempting more trials with a set up exactly as pictured. I suspect that each framed glass will need to be leveled with small weights added at the edge of the frame. We shall see.

Greg Rudzinski

From: Bruce J. Pennino
Date: 2015 Apr 18, 17:23 -0400

The mirror floating in pool is really elegant. I’m jealous. I now regret all of my effort to use a steel plate with leveling screws, plus all of the other refinements I built into my “system” so I could use it on steep uneven ground etc.

 

Simple is best. Accuracy of plus/minus 1 mile is probably  happenstance good fortune. With a quality sextant I would believe  plus/minus 1.5-2 miles.  What is typical best  accuracy with mirror or pool of fluid?

 

Bruce