NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Mark 3 and Low Cost Celestial
From: Bill Murdoch
Date: 1997 Jan 31, 14:33 EST
From: Bill Murdoch
Date: 1997 Jan 31, 14:33 EST
From: W. S. Murdoch, Polymers D&C (Kpt. 1027)
Subject: Mark 3 and Low Cost Celestial
If you restrict yourself to the Sun, there is no reason to pay the $270 for
a Celesticomp V. The little bit of programming for a 200 year, 0.1' accuracy
solar almanac and all the reduction formulas will easily fit in a pocket
programmable calculator. You enter the date, time, dead reckoning position,
sextant reading, index error, height of eye, temperature, and pressure. The
calculator returns the intercept and azimuth. You can program the calculator
yourself. I have written the instructions for doing it with three different
calculators.
Practical Boat Owner (London) published the first in January 1994. It uses a
TI-67 Galaxy calculator that sells for UKL 15 ($25) in Europe. I have not
seen the calculator for sale in the US.
Cruising World published the second in March 1996. It is for a TI-81. The
calculator sells for about $75, but is required in some high schools for
analytical geometry and calculus making many available used for about $25.
Because many schools require a TI-82 calculator rather than a TI-81, I have
rewritten the TI-81 program to run on a TI-82. The going rate for a used
TI-82 here is $25 to $50. New they are $80 to $90.
If you want to give it a try, drop me a note, let me know what kind of
calculator you have, and I will mail you a copy.
With a $39 sextant, $25 used calculator, and a wrist watch you have a pretty
good backup for a GPS. You are certainly in better shape than almost any
navigator on the sea before 1850.
Bill Murdoch
