Astronomical line of position (Sumner)
Línea de posición astronómica (Sumner)
- Date
- 1837 (publicado en 1843) · confidence high
- Place
- Off the Pembrokeshire coast, Wales, United Kingdom
- Credited to
- Thomas Hubbard Sumner
- Field
- Movement
What was discovered
With his ship in cloud off the Welsh coast, Sumner computed latitude from three assumed longitudes and saw the positions fell on a straight line. That line, perpendicular to the Sun's azimuth, is where the ship can be, so two lines give a position.
He found it in December 1837 and published it in Boston in 1843 as 'A New and Accurate Method of Finding a Ship's Position at Sea'.
What it led to
- a fix from two celestial observations by intersecting lines
- the Saint-Hilaire intercept method
- practical celestial navigation in the 19th century