NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Martelli's Time-Sight Tables
From: Doug MacPherson
Date: 2012 Dec 23, 07:51 -0800
From: Doug MacPherson
Date: 2012 Dec 23, 07:51 -0800
I ordered a copy from India by way of ABE books online. I will let you know how it turns out. Doug Sent from my iPhone On Dec 22, 2012, at 7:12 PM, Hewittwrote: > > 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 > > > Sent from my iPad >