He assisted in the preparation of the American Nautical Almanac for 1857.
While the system of counting from the capital of the country is still used for local purposes, the tendency in recent years is to use the meridian of Greenwich for nautical and international purposes.
He was then for a short time in the Nautical Almanac office.
This important proposal, the germ of the Nautical Almanac, was approved of by the government, and under the care of Maskelyne the Nautical Almanac for 1767 was published in 1766.
A mean degree of the meridian being assumed to be 69-09 statute miles of 5280 ft., the nautical mile (A l b - degree) is taken as 6080 ft., which is a sufficiently close approximation for practical purposes, and the distances between the knots are made to bear the same relation to 6080 ft.