A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Lloyd Browne
Date: 2019 Feb 16, 19:24 -0800
The 1866 diary of the navigator (Surveyor Robert Henry Edmunds) on a voyage from Darwin Australia to Kupang in the Dutch East Indies ends daily entries with the following: Entry for 15 August 1866: Lat 12.18.30 S. Long 128.55.0 E. Oysina point N. 70.W 338 miles. Entry for 16 August 1866: Position at noon; Lat 11.58.0S; Long. 127.22.0E. Distance 93 miles Oysina point N. 67 W 245 miles.
Is there anybody out there who can explain what is going on? Is "Oysina" shorthand for sigma y sin alpha - part of a trig equasion/solution? How can Edmunds project his calculations so far over the horizon? And what is the purrpose of his doing so?
Edmunds was a gifted navigator. I have followed the tracks of his explorations in the wilds of Arnhem Land (in Australia's Northern Territory) mainly on the basis of his recorded latitudes which rarely differ from GPS readings by more than 200 metres. Conversely his longitudes are rarely accurate - possibly.because of a faulty chronometer.
I would like to get some idea of the extent of his navigational knowledge so that I can include it in the biography I am currently writing.
Dr LFS (Lloyd) Browne