Celestial Navigation: using the Sight Reduction Tables Pub. No. 249

I found this text on Celestial Navigation to be one of the clearest introductions to the subject I’ve read. It covers every type of sight: Sun, Moon, Planets and Stars. It covers all the details at a leisurely pace to make sure you learn each step of the process before moving on to the next. There are plenty of examples and exercises to check your understanding.One of the outstanding strengths of this text is the emphasis on estimating ahead of time what to expect as a check against gross errors. There are plenty of diagrams and graphics to help you get an intuitive grasp of what you are doing at each stage of the calculations.It also covers in detail how to estimate the best times to take morning and evening sights, and gives multiple methods to preselect what stars and planets to use for those sights.The last two chapters cover finding the Main constellations, other uses of the sextant and how to use a scientific calculator to determine Hc and Z instead of using Pub. 249.Finally there is an accompanying website where you can download extra resources to use with the book: marinenavigationbooks.comYou can’t go wrong learning Celestial Navigation with this book. Happy Reducing!

A thorough treatment of the subject without bogging down in theory. This is clearly a “textbook” as used by the author in his celestial navigation classes. It covers all the usual elements of the art. A serious student, using this manual, can learn celestial navigation. I highly recommend it. On the other hand, it is perhaps too thorough for the average, older small sailboat sailor. The volume of material may be more than most want to wade through. The author is French Canadian and it shows in his superfluous additions to the basics. In a surprising omission, while discussing high frequency broadcasts of UTC he fails to mention that Canada also broadcasts UTC on HF. As the attached photograph shows, his site form treats one observation per page. In a small confined sailboat working on a small navigation table, a separate page for each observation is undesirable. Already herding the nautical almanac, site reduction tables, UPS, a calculator and plotting tools, keeping track of superfluous pages just makes the work more tedious. A single sheet of paper for a sight form to reduce three observations would be much appreciated. In conclusion, a ‘serious’ student will find this excellent manual all he needs to learn how to find his position using the Heavens.

As a recreational sailor who has aspirations of making a transatlantic crossing I wanted to learn celestial navigation. I had previously purchased other books on the subject which were not particularly helpful. Dominique Prinet's Celestial Navigation presents this difficult subject in a logical sequenced fashion that facilitates understanding of the material. The practical examples and worksheets allow the reader to gain confidence. I wanted to learn this subject as a back up practical skill. After reading the book I gained a new respect and fascination for the time honored subject of celestial navigation! When we make the crossing, Celestial Navigation is going with us!

This is a very useful book. I thought it included the 249 site reductions tables; only an excerpt used for explanation. Maybe I didn't read carefully.

The clearest written book I have found. I have purchased three other books on the same subject. This one is the best for understanding the concepts and steps needed to plot your lines of position. The author goes step by step in developing the concepts. Good examples are provided for practice. In order to remember what to do, one must practice. Very clear, excellent, Sight Reduction Work Forms are provided. Relevant Nautical Almanac tables for practice problems are provided. Partial Pub. 249 Tables are provided. To plot the lines of position, you will have to obtain VP-OS, Universal Plotting Sheet, and plotting instruments.

Good book.

VERY GOOD

Great instructional book.

My celestial navigation skills were getting rusty. A great book to relearn all the things I forgot

This book is very clear with step by step detail, worked examples and best of all the author's approach always encourages you to verify things by looking at the real world which lies behind the figures. He has obviously given much thought as to how to present things to someone wanting to learn. I have found this very helpful because at each step of the way you get a thorough explanation of the background and at the same time you learn to check for yourself and you have greater confidence because you can relate your workings to the world out there. If one works through all the examples and exercises one ends up with a good understanding of the subject as well as a knowledge of what to do and more importantly why you are carrying out the procedures involved in sight reduction. I have found the great danger in this area of navigation is learning procedures without a full understanding, you can just forget because you have no real understanding of what lies behind each step and unidentified errors can breed.I have tried other books; Mary Blewitt - very very brief, not enough to fully absorb it all. David Burch - fantastic tome but he's a physicist and it shows as the most 'professional' but perhaps not for idiots like me, although he does advocate and explain the use of scientific calculators as a reliable & accurate means of sight reduction which is good; Langley-Price/Ouvry Ocean Navigator is a much too heavily edited version of Kenneth Wilkes 1974 or 76 editions of Ocean Yacht Navigator, I would not recommend Langley/Ouvery because too much explanation and background has been taken out, but if you want only the procedure it might work for you. The original Wilkes Ocean Yacht Navigator is better with more explanation and it offers a much better overview of other useful info like the trad Hav & Cos formulae, the Traverse Tables and the ABC tables, finally if you would prefer a peek into an earlier or pre-computer approach and a demo of the Haversine formula but presented in the context of yachting I would also highly recommend Peter Clissold's Yachtmaster Offshore and Ocean 1977 which covers a lot and although some of it is inevitably out of date, it is extremely useful because after all so much actually doesn't change out there and he is very succinct on astro-navigation- you even get some old black&white practice charts with fathoms!But so far best of all just to learn the subject well all you need is D Prinet's Celestial Navigation and perhaps his accompanying exercise book.Thankyou.

Celestial Navigation and Celestial Navigation exercises – Dominique F. Prinet.Thank-you Mr. Prinet for your two excellent books guiding the reader through the intricacies of Celestial Navigation. You not only show how useful the method still is now, but explain all the very clever concepts behind the method developed over the centuries to navigate with the sun, the moon, the stars and the planets.The clear explanations illustrated by many simple graphics, and all the exercises you offer for practice, show the way towards navigation with celestial objects, a very rewarding approach when compared to the use of obscure electronic systems.Your reference to illustrious world navigators such as Cook, Shackleton and Marc Saint Hilaire, turn the subject into a fascinating human endeavour. Your books bring back some of the poetry of ancient sailing traditions, when audacious explorers set out from their small coastal villages to explore the oceans well beyond the horizon.Michel Didier

To the Point on many Levels A Fifth of All that is Necessary in Sailing And Viewing the Other 4 Fifs are Spent in other Domains ⚖️

Very good. Straight forward, easy to follow. Thoroughly recommended.