NavList:

Tony
You don't need to use the averaging mechanism for shots on the ground; it's only there to minimise acceleration errors when used in flight.  Using the averaging mechanism on the ground, you'd die of boredom before you'd finished.  If you have a seperate window for the average value compared to the index mirror reading as in the Smiths, Kelvin, Hughes sextants, then a separate check should be to set a fixed known value on the index scale, run the averager, and compare the two results. The difference should be no more than a minute or two of arc, and the run-time should be within a couple of seconds of that selected.  We're talking about 1940s alarm-clock mechanisms here. Don't expect too much.  DaveP