Definition of lunar observation in US English:

lunar observation


  • A measurement of the position of the moon in order to calculate longitude from lunar distance.

    • ‘At the Greenwich Royal Observatory Halley used the first transit instrument and devised a method for determining longitude at sea by means of lunar observations.’
    • ‘He speculated that he would continue to ‘amuse’ himself in attempting to determine Monticello's longitude but with lunar observations.’
    • ‘If you had a chronometer, you would use it to measure longitude all the time, not just "when lunar observations were impractical."’