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Hewitt,

Using Frank's Martelli PDF I was able to do a Moon time sight this evening to near perfection. The tables are easy to use but I do not like working in hours, minutes, and seconds when LHA could be given directly saving several steps.

Here is how the formula may compare to the tables:

ArcCos[ (SinHo ~ SinLSind) / (CosLCosd)
Tab#V Tab#III Tab#II Tab#IV Tab#I

Greg Rudzinski

[NavList] Martelli's Time-Sight Tables
From: Hewitt Schlereth
Date: 22 Dec 2012 19:12
I ordered this book from Amazon and it came yesterday. Full title is "Short,
easy, and improved method of finding the apparent time at the ship."

It's a trade paperback, and I have to say Hewlet-Packard made a nice job of
it. The signatures are stitched, so they shouldn't come loose. The only
shortcoming with my copy is the print on page 42 and pages 44 thru 47 of
Table V is light (but still quite legible).

The tables are I thru VI and the method takes them in that order. What you end
up with is LHA expressed in time units, so you have to convert to the angular
units we are used to- 1 hour = 15*, 4 mins = 1* ...

After working through his English example (the same data is used for
directions in French, German, Italian and Spanish), I ran the example through
my HP 35s using the sine/cosine formula and it gave an answer 1.0' less than
Martelli.

Then I tried M's table with Greg's 12-17 time sight and again the difference was 1.0'.

My 1972 Bowditch noted that Martelli's method was still popular. Having been
an active navigator then having tried it now, I can see why. There are 6
tables, but they are short and logical. In neither of the cases I tried did I
have to do an interpolation.

My one cavil is to wish M had set out the formulas he used. I have the same
gripe about the Concise SR table in the NA.

Net of everything, though, Martelli's book is an agreeable stocking stuffer for myself.

Hewitt

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