Abstract: This invention provides an improved method and apparatus for celestial navigation. A reference spherical triangle is established from the coordinates of the ground position of an observed selected celestial body and an assumed position for the observer. A second right spherical triangle is then derived from a functional relationship between the first triangle and the observed height of the celestial body. The location of the end of the hypotenuse of the second triangle opposite the ground position defines a point of position on a line of position for the observer. The compass bearing for the line of position is functionally derived from conventional relationships and the line of position may be plotted through the point of position. Plotting means are provided to maintain the spaced relationship between lines of longitude and lines of latitude as a function of latitude for a mercator map projection and to directly plot the point of position on the plotting means.