This chapter details the creation and management of the Nautical Almanac, one of the Board of Longitude’s most important concerns. Appointed Astronomer Royal and thus a Commissioner of Longitude in 1765, Nevil Maskelyne oversaw its publication and that of associated texts, directing the work of a group of mathematical computers overseen by comparers. Hierarchical organisation and increasing costs preoccupied much of the Board of Longitude’s subsequent affairs. Calculated up to a decade in advance, the Nautical Almanac became a symbol of the Board’s repute among foreign academies and observatories, although its accuracy was later subject to satire and criticism. After Maskelyne’s death, work seems to have suffered and its management was overhauled by the Longitude Act of 1818 that brought it under Thomas Young’s management. Controversy wracked the Board’s direction of the Nautical Almanac for the next decade. Its assignment from 1831 to the astronomer William Stratford as superintendent was a major element of the aftermath of the Board’s abolition.

This chapter reinterprets the demise of the Board of Longitude in 1828, which has been seen as resulting from reformist pressure or financial retrenchment. Such accounts underestimate continuation of the Board’s activities, notably managing chronometers, producing the Nautical Almanac and providing scientific advice. Changes were initially driven by Joseph Banks’s interests, notably the appointment of Royal Society fellows and Resident Commissioners including Thomas Young, who became secretary and a key organiser after Banks’s death. Schemes such as rewards for finding the Northwest Passage, improvement of optical glass, determining the figure of the Earth and the foundation of the Cape Observatory, were managed under Young’s aegis. The role of the Admiralty and its Secretaries John Wilson Croker and John Barrow were decisive. The Longitude Act of 1818 brought the Board under Admiralty control, and that of 1828 moved its work into the Admiralty. An Admiralty committee comprising Young and natural philosophers Michael Faraday and Edward Sabine was formed; the Nautical Almanac and chronometer testing remained within the Admiralty’s financial remit.