NavList:

Further, we must not ignore the very item which permits the LoP to be approximated with a line.  That is the azimuth to the body.   That further restricts the length to a segment of the circumference.

Brad
Your reminder prompts an interesting observation, which I’d never considered before. If you’re not where you think you are, how accurate is a celestial heading check?  In other words, if you’re using celestial to keep an inertial platform or similar aligned, what’s the chance of an unbounded runaway of position?  E.g. error in position leads to error predicted azimuth leading to error in heading leading to bigger error in position leading to bigger error in predicted azimuth and heading found and so on and so forth. DaveP