A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: John Brown
Date: 2014 Nov 3, 19:29 -0800
Greg wrote: "A final important note is that the Sun needs to be positively identified and not just a bright spot in the clouds."
Frank Worsley, Shackleton's navigator and Master of Endurance, describes his difficulties with cloud cover during the epic voyage of the 22 foot James Caird from Elephant Island to South Georgia in 1916. His technique, when the disc of the sun was obscured by cloud and too indistinct to use either limb, was to bring the centre of the bright spot down to the horizon. He claims in his book Shackleton's Boat Journey that averaging the altitudes could give accuracy to one minute of arc.