Maskelyne is buried in the churchyard of St Mary the Virgin, the parish church of the village of Purton, Wiltshire, England.

[12] He returned to England, resuming his position as curate at Chipping Barnet in 1761, and began work on a book, publishing the lunar-distance method of longitude calculation and providing tables to facilitate its use in 1763 in The British Mariner's Guide, which included the suggestion that to facilitate the finding of longitude at sea, lunar distances should be calculated beforehand for each year and published in a form accessible to navigators.

The three methods on trial were John Harrison's sea watch (now known as H4), Tobias Mayer's lunar tables and a marine chair made by Christopher Irwin, intended to help observations of Jupiter's satellites on board ship.

Both Harrison's watch and lunar-distance observations based on Mayer's lunar tables produced results within the terms of the Longitude Act, although the former appeared to be more accurate.

[14] On 26 February 1765 he had been appointed Astronomer Royal[3] following the unexpected death of Nathaniel Bliss in 1764; making him ex officio a Commissioner of Longitude.

The lunar-distance method could more quickly be rolled out, with Maskelyne's proposal that tables like those in his "The British Mariner's Guide" be published for each year.

He was to play a significant role in having marine timekeepers, as well as the lunar-distance method, developed, tested and used on board voyages of exploration.

[18][19] Maskelyne took a great interest in various geodetical operations, including the measurement of the length of a degree of latitude in Maryland and Pennsylvania,[20][13] executed by Mason and Dixon in 1766 – 1768, and later the determination of the relative longitude of Greenwich and Paris.

[22] In 1772 Maskelyne proposed to the Royal Society what was to become known as the Schiehallion experiment (named after the Scottish mountain on which it was performed), for the determination of the Earth's density using a plumb line.

Maskelyne performed his experiment in 1774 on Schiehallion in Perthshire, Scotland,[23] the mountain being chosen due to its regular conical shape which permitted a reasonably accurate determination of its volume.

[13] Maskelyne also introduced several practical improvements, such as the measurement of time to tenths of a second and prevailed upon the government to replace Bird's mural quadrant by a repeating circle 6 feet (1.8 m) in diameter.