Fixing a ship's position by the stars

Taking a sight with a sextant, timing it against a chronometer and reducing it with tables gave a position good to a mile or two after twenty minutes of careful work. A receiver gives metres in a second, at any hour, in any weather. What was ceded is the daily fix, and with it the arithmetic and the habit of looking up. The United States Naval Academy stopped teaching celestial navigation in 1998 and brought a short course back in 2015, on the argument that a satellite signal can be jammed or spoofed and a sextant cannot. That reversal is the shape of what remains held: not the routine work, but the fallback, kept alive by a small number of officers and ocean sailors precisely because the machine has one point of failure.