In 1984, Mr. Greenwood imported sextant from Davis Instrument Co., San Leandro, CA. His purpose was to learn complicated method of finding his position only from time and position of the sun. At that time, only available method of knowing his position were Loran and Decca system. Even Jambo jet plane carried sextant for emergency purpose.
sextant
Now similar to moors signal, GPS replaced sextant completely. Mr. Greenwood still keeps his sextant.