NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Timed Noon sights for position
From: Bill Noyce
Date: 2004 Jan 22, 16:46 -0500
From: Bill Noyce
Date: 2004 Jan 22, 16:46 -0500
That's how I would do it, but I don't think that's what Doug is doing.
Rather, it appears he precomputes an appropriate GMT, and makes a sight
at that time, assuming it to be LAN. I stand ready to be corrected...
-- Bill
-----Original Message-----
From: Navigation Mailing List
[mailto:NAVIGATION-L@LISTSERV.WEBKAHUNA.COM] On Behalf Of Fred Hebard
Sent: Thursday, January 22, 2004 4:42 PM
To: NAVIGATION-L@LISTSERV.WEBKAHUNA.COM
Subject: Re: Timed Noon sights for position
On Jan 22, 2004, at 4:07 PM, Noyce, Bill wrote:
> I'm still confused. Suppose the procedure you suggest does give a
> reliable latitude (I have some questions about that, but don't want to
> discuss them until I'm sure I understand the procedure.) It looks to
> me as if you must then choose among some of the following alternatives
> for a longitude:
I'm no expert on navigation, but isn't the following the basics?:
The noon sight gives your latitude directly as lat = 90 - altitude +
declination, where north declinations are positive for sights from the
northern hemisphere. No time involved.
The time at which you make the sight is noon, local time, and that with
GMT gives you longitude, with suitable correction using the equation of
time.
You get GMT from the chronometer or the radio.
