NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Life raft questions - knowing only GHA and sun's rising or setting
From: Stan K
Date: 2018 Nov 7, 17:39 -0500
From: Stan K
Date: 2018 Nov 7, 17:39 -0500
How about a little printed analemma in your life raft equipment?
Stan
-----Original Message-----
From: Tony Oz <NoReply_TonyOz@fer3.com>
To: slk1000 <slk1000@aol.com>
Sent: Wed, Nov 7, 2018 2:02 pm
Subject: [NavList] Re: Life raft questions - knowing only GHA and sun's rising or setting
From: Tony Oz <NoReply_TonyOz@fer3.com>
To: slk1000 <slk1000@aol.com>
Sent: Wed, Nov 7, 2018 2:02 pm
Subject: [NavList] Re: Life raft questions - knowing only GHA and sun's rising or setting
Dear Ed,
As I can imagine the life in a life raft - one has lots of time to watch the sky.
Assuming his watch is on UT - subtracting the UT of the sunrise from UT of the sunset one gets the daytime duration and also an estimation of the UT of apparent noon (by halving the interval). The latter immediately gives an estimate of his longitude: LHASun = GHASun + Lon, but at noon the LHA == 0°, so Lon == -GHASun as read from the watch.
But the problem remains: where to get the correct value of EoT for the day?
Regards,
Tony
60°N 30°E
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