1732-1811

English astronomer who established the celebrated Nautical Almanac (1766), whose tables and astronomical information were indispensable navigational aids. Maskelyne tested and devised better methods for determining longitude at sea; observed Venus's 1769 transit from which he computed the Sun's distance to within 1%; and calculated Earth's density, which compares well with presently accepted values, from plumb line deviation near Mt. Schiehallion, Scotland (1774). He succeeded Nathaniel Bliss as the Fifth Astronomer Royal (1765).