NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Lost in the South Atlantic
From: Stan K
Date: 2017 Jun 27, 03:58 -0400
From: Stan K
Date: 2017 Jun 27, 03:58 -0400
Frank,
I woke up in the middle of the night and could not fall back to sleep, so I decided to expand on my previous answer:
(BTW, as of right now, this has not appeared on NavList.)
I think you were daydreaming off the island of Trinidade, off the Brazil coast. Do you need more?
Assuming a lower limb sight, the location I calculated was 20º49.1'S, 29º00.7'W. The azimuth of the Sun was 314.6º. According to Wikipedia, the location of Trinidade, rounded to tenths of minutes, is 20º31.5'S, 29º19.5'W. This puts Trinidade 24.9 nm away, bearing 315º, putting it almost directly below the Sun.
The distance to the horizon for a height of eye of 25 feet is 5.8 nm. For something 24.9 nm away to be visible above the horizon, its height must be at least 265 feet. According to Wikipedia, the highest elevation on the Trinidade and Martin Vaz archipelago is 2030 feet, so it could be easily seen in clear conditions.
Stan
-----Original Message-----
From: slk1000 <slk1000@aol.com>
To: NavList <NavList@fer3.com>
Cc: slk1000 <slk1000@aol.com>
Sent: Mon, Jun 26, 2017 9:27 pm
Subject: Re: [NavList] Lost in the South Atlantic
From: slk1000 <slk1000@aol.com>
To: NavList <NavList@fer3.com>
Cc: slk1000 <slk1000@aol.com>
Sent: Mon, Jun 26, 2017 9:27 pm
Subject: Re: [NavList] Lost in the South Atlantic
Frank,
I think you were daydreaming off the island of Trinidade, off the Brazil coast. Do you need more?
BTW, no conflict the weekend of the symposium. I'll register tomorrow.
Stan
-----Original Message-----
From: Frank Reed <NoReply_FrankReed@fer3.com>
To: slk1000 <slk1000@aol.com>
Sent: Mon, Jun 26, 2017 8:20 pm
Subject: [NavList] Lost in the South Atlantic
From: Frank Reed <NoReply_FrankReed@fer3.com>
To: slk1000 <slk1000@aol.com>
Sent: Mon, Jun 26, 2017 8:20 pm
Subject: [NavList] Lost in the South Atlantic
Yesterday, 25 June 2017, I was sailing in the South Atlantic aboard my 140-foot schooner "Sonho Acordado," and I was lost! Well actually, my sextant was lost for a few days, but finally it turned up, stowed in the wrong compartment (that's the trouble with such a large yacht). I took a sight of the Sun about three hours after local noon, give or take fifteen minutes. My raw sextant altitude was 29°20.5' at 16:48:30 UTC. There's no index correction since I always maintain my sextant with index error zero-ed out. My height of eye was 25 feet or so. And by good fortune, there was a rocky island visible on or beyond the horizon almost directly below the Sun. Where was I?
Frank Reed
