A FIX AT sea or in the air can be obtained by the methods and tables indicated below by means of the simultaneous observations of altitude and azimuth of a single celestial body in a very simple and practical way: 
The altitude is taken by any bubble sextant or octant.
The azimuth is taken simultaneously by any well-adjusted gyrocompass or any well-adjusted magnetic compass.
The time is taken by means of double split-second stop watches from the sidereal, civil, or solar time chronometers. The stop watches give the true or “no correction” sidereal, civil, or solar time at sight.
The calculations are made by any ordinary table of trigonometric logarithms containing log tan, log sec, log cosec for every 1' or less.
The plotting is ordinarily done on a Mercator chart.