# NavList:

## A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

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Re: Latitude and longitude around noon
From: Francis Upchurch
Date: 2017 Mar 3, 17:27 -0000

```I tried 3 methods.
1) Quick and dirty. Assume noon alt 41deg30',Ho 41*36'36'', ZD 48*23', Lat 41*26.4'.
EoT=+12'5''.LAN Greenwich=12.12.5. = 4.48.35 time difference.=72* 8.7' W
2) Slow and dirty. Graph. LAN 16 59 16 gives Long 72*2' W
3)equal altitudes gave same result as 2).
Did not know to correct for the 1knot northing of the sun. Please explain Frank.
Best wishes
Francis

-----Original Message-----
From: NavList@fer3.com [mailto:NavList@fer3.com] On Behalf Of Frank Reed
Sent: 02 March 2017 21:34
To: francis@pharmout.co.uk
Subject: [NavList] Latitude and longitude around noon

Four hours ago I took a series of Sun sights around local noon. Here's the raw data:
16:35:30, 41° 13.0'
16:40:55, 41° 20.9'
16:48:02, 41° 25.8'
16:55:39, 41° 28.8'
17:00:38, 41° 30.0'
17:02:46, 41° 28.7'
17:06:22, 41° 27.3'
17:12:25, 41° 23.3'
17:19:18, 41° 15.2'
17:23:19, 41° 09.0'
Times are UT. Altitudes are Sun LL, as usual. Height of eye 24 feet. Index
error was about 3.8' on arc. Can you determine my latitude and longitude from
these sights? How many different ways can you come up with to get a fix from
these observations? Incidentally, my "northing" speed was zero, but the Sun
is northbound at about 1 knot this time of year.
I was able to shoot the Moon and Venus, too, so there were ample opportunities
to get a celestial fix today. The weather was chilly and blustery. Great
waves! See photos.
Frank Reed

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