Customer Reviews

Celestial Navigation in the GPS Age

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4 star:		(2)
3 star:		(1)
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Written by physicist, pilot, sailor, and fifty-year veteran of celestial navigation John Karl, Celestial Navigation in the GPS Age is a practical guide to the skill and science of celestial navigation for offshore navigators. Compact without being abridged, Celestial Navigation in the GPS Age is tailor-written for the modern era of computers, calculators, and online resources. Though the traditional methods of "working a sight" is covered, the meat of Celestial Navigation in the GPS Age carefully instructs the reader in the use of a simple and inexpensive scientific calculator. From the basics of coordinates, to sun sight reductions and lunar distance sights, to sextant adjustments and altitude corrections, and an exhaustive wealth of appendices, Celestial Navigation in the GPS Age is an absolute "must-have" for offshore navigators and a readily accessible self-teaching tool.

I've read through,looked at several books on celestial navigation, a subject that has captured my interest. Mr. Karl's book offers about the clearest explaination of "the navigational triangle" that I have come on. Historical comment on the sad fate of Capt. Sumner, of Sumner line navigation is also interesting. A small reproduction of the painting, Capt. Sumner Discovers the Celestial Line of Position catches the viewers eye too.

Most interesting and encourageing to me was the following. In the section on the navigational triangle, the author made a statement that seemed wrong. Curious about this, I e-mailed the author, c/o his publisher, Paradise Cay Publications of Arcata California and Celestaire of Wichita, Kansas jointly, the people at Paradise Cay sent my inquire on to Mr. Karl, who was kind enough to respond, in effect, turning on the light in a poorly lit room.

I cannot possibly say enough good things about this book. It is so well authored, so well written, and so thorough that anyone interested in CelNav would be completely amiss not to buy this book. Because I spend so much time studying the subject, I came to a point where I began studying the algorithms, celestial mechanics, and mathematical theory behind CelNav and wanted to move into deeper, more intensive areas of the subject with the intention of eventually being able to calculate the very orbits that we derive our almanac data from....however, I was unable to break into this seemingly unattainable realm because of the overwhelming circular nature of the texts and dicussions that tend to predominate regarding the subject. THIS BOOK was the key that unlocked those areas for me. You will find yourself amazed at how much "meat" each and every line of this book contains, it's as though each sentence offers new and equally important light to the study of CelNav. You will, as I did, I'm quite sure, read and re-read this book with the result that your understanding of CelNav will be deepened a hundred-fold. If the price of books were determined by the significance of their contents, this one would cost millions.

This book is possibly not the best introduction or a first reading of celestial navigation. The author apparently attempts an intuitive approach to the subject by throwing a lot of minimally explained concepts and nomenclature at the reader in order to demonstrate how sight reduction with a calculator is not that difficult at all. In so doing, he may be scaring a few novices into thinking that the learning curve for celestial is unreasonably high.

That being said, it's quite valuable to the advanced student of celestial. It's formulas for both Hc and azimuth are reasonably well explained as is the formula for clearing the lunar distance. In addition, for all readers, both novice and advanced, in a most gratifying way the author explains several basic concepts and realities in celestial navigation which for some reason have always been left out of even the best starter books, probably since the days of Sumner and St. Hilaire. Perhaps these omitted concepts may have been one of the author's pet peeves in his own learning of celestial, and he seems bent on filling in the missing info, and teaching the subject right. He does a good job of this.

If you like an intuitive approach, you can make out with this book as a first reading on the subject. However, if you prefer the pedantic approach of thoroughly learning the concepts and nomenclature first, and then working the problems, the best books for beginners are still Mariner's Celestial Navigation by William P. Crawford (the ridiculous used prices reflect the quality of this book) and the old standard American Practical Navigator (Bowditch). These books offer more details and explanations first, and then the problems are solved.

In all fairness, if you are a beginner in celestial, it pays to buy this book and read it in conjunction with another book on the subject. That is, when you complete a chapter by Crawford or Bowditch, look for and read the same information in this book for a second explanation and then go back to the next chapter in Crawford or Bowditch.

For this second explanation alone, it's worth a lot more than $25.

Ron DiGiovanni

Easton, PA

after some searching on the internet i found this book. i was looking for a study book for my students deck officer at a maritime collge. i found this book to be easy to read, very good for students for whom english is NOT their native language.

the examples are clear and easy to understand. i think this book can be used to only teach the basics or entice the students to go deeper into the celestial navigation.

The theory portion of Celestial Navigation in the GPS Age is OK. My problem is that John Karl has enough press this and press that on a calculator to make it confusing. Now if Mr.Karl had actually told the reader what $10 calculator his book referred to possibly I would have purchased same and stuck with him.

Example: Recall [2] press SIN, press -, recall [1], press x, recall [3], press SIN, press =, press /, recall [1], press COS, press /, recall [3], press COS, press =, press INV, press COS.

Unfortunately my $14 TI-30X IIS does not work in this order. One presses the function then the number. Yes, I can read backwards but I prefer left to right. So what $10 calculator is Mr.Karl using?

To be fair I did stop reading in the sight reductions chapter but only because of frustration with push this and push that button on some unknown $10 calculator. I'm seriously thinking about a slide rule now.

I have an old Davis Mark 12 sextant used for basic Sun work 30 years ago. My current plan is to learn celestial navigation in much greater detail for extended solo cruising but this is not the book for me, at least at the moment. Your inner workings may vary!

Who knows, one day I may find a calculator that works with this book and reread it. I am quite sure there is some good content deeper inside but for now I will be wiping the cobwebs off of Celestial Navigation By H.O. 249 by John E. Milligan I leaned on so many years ago.

This site for free celestial nav software download may be of interest. Aeronautical engineer and sailor for 50 years.