NavList:

Bill writes:

"... why would one need to take multiple sights and
average (by any means)?  The inquiries (as I recall) came from professional
sailors on commercial ships.

My answer would be rather blunt.  A large vessel averages the wave height
for dip plus height of eye for dip correction.  A small vessel attempts to
make the observation at the top of a wave. Given a moments calculations, 6'
off the top of a "real" (not averaged) wave and dip changes by 02!4."

 

Bill makes a good point.  Small boat sailors have more need of a method of evaluating their sights, due to their generally difficult conditions of observation.

 

Gary tells us he plans to use the slope technique with a mirror replacing a horizon, thus on land under generally favourable conditions.  I will be interested in seeing the results, and since the technique was once taught to land surveyors using theodolites as just one technique towards improving accuracy, it should be able to be scaled to Gary's requirements, even if the pattern of his sights shows considerably less variation than is typical of observations made from a small boat at sea. 

 

However without that scaling, ie; if the pattern of sights exhibits little variation, then there may not be much to be gained from that, or indeed any analysis.