Customer Reviews

Celestial Navigation for Yachtsmen

5 star:		(8)
4 star:		(3)
3 star:		(1)
2 star:		(1)
1 star:		(0)

 

 

Having struggled with the arcane mechanics of celestial navigation for the past three years it was an immense relief to discover a tome that could lead me through both theory and practise in less than 80 pages! Ms. Blewitt's matter of fact approach to the complexities of sun and star sight reduction etc. is refreshing indeed. For anyone contemplating offshore navigation of any type, this book is worth a dozen night school courses.

I was concerned that such a small book (just over 100 pages) could contain enough information about celestial navigation to make my sextant useful. I shouldn't have been. The book is bypasses hype, lore and commentary and deals strickly with the topic at hand. It can be tough going but the book is written clearly enough so as not to be confusing on such the subject.

I thought it was going to take years to learn celestial navigation. After reading Celestial Navigation for Yachtsmen I was plotting my position within miles of my known position in just a few days (I was using a plastic sextant Mark 15). The first 22 pages of reading requires a lot of thought and time to absorb the information but after one understands the main concepts the rest of the book becomes easier to follow. I highly recommend this book.

Overall, the book does a good job explaining how to navigate by the sun, moon and stars, but it does leave some questions unanswered and makes jumps without explaining how the jumps were made. For example, on page 31 the author writes "Against the LHA of 348 (degrees) we read Hc: 15 (degrees) 16', d60 Z169 (degrees)", but does not tell you why you use row "12" in the table. Is it because 360-348=12? You are left to guess.

This book is exactly what I expected it to be and exactly as advertised. Its short length makes it useful for quick reference. It is clearly written.

Celestial navigation, like knots and splices and reading maritime charts and tide tables, is one of the essential sailing skills. Whether you are a daysailer, weekender, blue water cruiser or lone circumnavigator, there WILL come a time when the GPS quits, the Loran won't work, and you're going to say, "Where the &$@!* am I?". If you haven't learned celestial nav at that point you had better be a real quick study or have hired a good estate planning lawyer.

But assuming that Clarence Darrow Dershowitz Kunstler Belli Nizer, Esq. isn't in your crew, Mary Blewitt's book is a good thing to have. Brief, concise, and Ptolemaically simple to understand, Blewitt takes the hocus-pocus out of asking the heavens for directions. The difficulty with learning celestial nav isn't so much the math (as most people want to believe) as it is that modern man is SO far out of touch with the natural world that looking at the night sky is like looking at---something dark and mysterious. However, add a few very basic, easy-to-grasp concepts to your skill set and your Sunfish will suddenly become the Santa Maria.

Knowing celestial navigation will help you to sail anywhere and, even better, to know where you are when you get there. To that end, this book is an invaluable learning tool.

Before crossing the Atlantic in 1978 on my 22' sailboat, I read many books on celestial navigation and became convinced that it was an inpenetrable subject and then, on reflection, I realized that that could not be so as so many navigators had had less geometry etc than me. I figured the authors did not really know what they were talking about. And then I came across Prof. Blewett at the Boston Museum of Science, teaching on 10 Wednesday evenings. After the first lecture, on the noon sight, she said, if you your boat is going faster than 20 kts then you don't have to come back for more. That is all you need. She was absolutely right. But I did continue -- I took the course so I could do the fun-and-games of star sights too. I can now teach her course in 45 minutes.

An excellent and clearly written book.
Easy to follow and understand.
A must for anyone interested in this subject.
Written by an expert for both beginners and experts.
I am delighted I purchased it.

My volume is the revised edition of 1994. Having been in print for so many years, this slim volume could be termed a "classic." However, all good things come to an end and so should this book. The writing is archaic, the graphics are old-fashioned and confusing, and there is at least one omission in this edition.
Purportedly written for a novice, it isn't. I have a thorough knowledge of celestial navigation and was confused trying to follow her descriptions of angles such as "Add angle ZQX and angle XQE" etc. In figure 8, point Z is missing. She describes "apparent altitude" but does not label it "Ha"; rather she skips from Hs to Ho. She introduces the term sidereal hour angle on page 6, and refers the reader to page 40 for a definition. I suppose the biggest fault of the book is that it is simply too dated. There are much better books nowadays on celestial nav for beginners, written in clearer language with more descriptive graphics. Throw this one in the ditch bag to take with you if you have to abandon ship.

Haven't completely read the book yet. Difficult to understand the principles and theories- when are in fact- laws. I know of no other way to explain what the author himself is attempting to teach. Am having difficulty applying what I have read. Very challenging, but I hope to overcome my shortcomings and embrace the knowledge contained within this book.