What do the results of this mission tell us.
Several things.
First, we would not be this accurate unless the sextant, clocks, and almanac were not very close. In celestial navigation, everything is linked together, and the result can not be right without everything else in the tool box being right also.
The error triangle behavior where it drifts toward the assumed longitude at higher latitudes is exactly what should happen on a sphere. Since we are using spherical trigonometry to find our position, the results should be plotted on a sphere. The results don't know how we are plotting them, so the error triangles go where they are supposed to on a sphere. The method works...but needs the correction because of the map projection.
The correction term certainly seems to be the sec LAT or 1/cos LAT. And this equidistant cylindrical projection is the one that provides it. It even looks right.
I think this strong evidence that we know what map projection the developers used. And I think it is strong evidence that we are on the right track here.
The greater error at higher latitudes might be a warning though of the limits of plotting positions on cylinders.
Next mission of this voyage will be a closer look at the clocks...radio messages from reaper7 and vanjast need to be answered.
