https://en.wikipedia.org/wiki/Celestial_navigation https://en.wikipedia.org/wiki/Celestial_navigation > Sextants can be read accurately to within 0.1 arcminute

https://en.wikipedia.org/wiki/Celestial_navigation https://en.wikipedia.org/wiki/Celestial_navigation > Sextants can be read accurately to within 0.1 arcminutes, so the observer's position can be determined within (theoretically) 0.1 nautical miles (185.2 meters, or about 203 yards). Most ocean navigators, measuring from a moving platform under fair conditions, can achieve a practical accuracy of approximately 1.5 nautical miles (2.8 km) Some napkin math, assuming using a Sextant to achieve similar accuracy of 0.1 arcminutes on the Moon, because Moon is about 3.7 times smaller than Earth, that 0.1 arcminutes is around 50 meters on the Moon. One can expect extremely clear sky and certainly not riding waves on the Moon, so the practical accuracy should be close.