A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Herman Dekker
Date: 2021 Sep 15, 13:40 -0700
Lat/Lon near Noon one other way to calculate it.
I thought I calculated Frank’s problem by the TI-89 calculator with Starpilot program.
First calculate with CoarseMadeGood and SpeedmadeGood program the result of boat and current movement.
Outcome Course 158° Speed 4,3 Kt
The TI-89 calculator asks the DR position and the HE , for the sight reduction
that is not given so I had to calculate roughly myself.
I am educated by Frank LAT=ZD + Dec. ZD= (90°-Ho)
I choosed the sight with max measured height.
UT 16:39 Hs=73,075° Ho=73,075+0,216=73,291°
Almanac for 22-mai-2022 midday gave about Dec=20,44
Sun shadow points North. So LAT=+ZD + Dec
LAT=(90°-73,291°) + 20,44=37,15° N
Noon is around max. measured height at ~UT=16:39
Converted UT to Lon, at UT 16:39 Lon = 69,75° W
For HE, reverse calculated from given info HE=8,3 feet
Now typed al six sights in the Sight reduction program.
Then simplistic did Fix by computation at UT 16:39:15 and the answer is:
LAT 37°11,4’ N
LON 70° 12,5 W
Even as the lops cross under shallow angles, a good result.
At UT 17:00:00 the position is:
This my contribution on the Noon problem.