Time and Navigation: The Untold Story of Getting from Here to There

by Andrew K. Johnston, Roger D. Connor, Carlene E. Stephens

If you want to know where you are, you need a good clock. The surprising connection between time and place is explored in  Time and The Untold Story of Getting from Here to There , the companion book to the National Air and Space Museum exhibition of the same name.

Today we use smartphones and GPS, but navigating has not always been so easy. The oldest "clock" is Earth itself, and the oldest means of keeping time came from observing changes in the sky. Early mariners like the Vikings accomplished amazing feats of navigation without using clocks at all. Pioneering seafarers in the Age of Exploration used dead reckoning and celestial navigation; later innovations such as sextants and marine chronometers honed these techniques by measuring latitude and longitude. When explorers turned their sights to the skies, they built on what had been learned at sea. For example, Charles Lindbergh used a bubble sextant on his record-breaking flights. World War II led to the development of new flight technologies, notably radio navigation, since celestial navigation was not suited for all-weather military operations. These forms of navigation were extended and enhanced when explorers began guiding spacecraft into space and across the solar system. Astronauts combined celestial navigation technology with radio transmissions. The development of the atomic clock revolutionized space flight because it could measure billionths of a second, thereby allowing mission teams to navigate more accurately. Scientists and engineers applied these technologies to navigation on earth to develop space-based time and navigation services such as GPS that is used every day by people from all walks of life.

While the history of navigation is one of constant change and innovation, it is also one of remarkable continuity. Time and Navigation tells the story of navigation to help us understand where we have been and how we got there so that we can understand where we are going.

Genres: Science, History, Ebooks

224 pages, Hardcover

First published April 28, 2015

Reviews

[Jamie Smith · Rating 3 out of 5]

Mankind has been going to sea for thousands of years but it wasn’t until the 1700s that it became possible to find one’s precise location when out of sight of land. Before that, it had been possible to find the latitude (position north or south of the equator), but longitude (position east or west of the prime meridian) required very accurate clocks. (The best book on the development of the chronometer is Dava Sobel’s Longitude.) The prime meridian runs through Greenwich, England, but only because the British decided to put it there. Others proposals would have had it go through Paris, or even Mecca, since one place is a good as another for navigational purposes, but no one has come up with a compelling reason to move it. If you know the exact time of some celestial event in Greenwich, such as sunset or the position of the moon or one of the navigational stars, and then calculate when that same event occurs where you are, the difference in time will tell you how far east or west of the prime meridian you are.

This book is not a primer on celestial navigation. If you are interested, Bowditch’s American Practical Navigator has been the go-to guide for generations of sailors. In fact, Time and Navigation is not technical in any way; it was created as a book to accompany a Smithsonian exhibit of the same name. So long as you are not looking for detailed explanations, this is not a bad thing. The book follows the advances in navigation tools for land, sea, air, and space, and the print version is full of beautiful photographs. It includes information on the inventors of the devices and the problems they were trying to solve. Finding a navigational fix in a fast moving airplane adds complications not faced by shipboard navigators, and the solutions that were devised where elegant and ingenious.

Today, GPS has turned navigation into a trivial task, but those satellites can be jammed or destroyed, so the day of the professional navigator may not be over. The U.S. Navy, recognizing the potential for trouble, has reintroduced the study of celestial navigation to its officer training programs, and so they still stand out on the bridge wings at morning and evening twilight and swing a sextant the same way it has been done for almost three hundred years, although they no longer have to make the multi-step sight reduction calculations by hand (a significant aid to sailors whose brains are fogged from sleep deprivation – which is just about all sailors at all times).

This book is not just for those with an interest in navigation. Anyone who enjoys ingenious solutions to complex problems will find a lot to like here.

[Dave · Rating 3 out of 5]

This book is based on an exhibit at the Smithsonian's National Air and Space Exhibit. It takes us from the earliest days of navigating by the stars to today's satellite navigation systems, examining the challenges of navigating on sea, land, air, and even in space. One of the key themes is that you can't accurately navigate without knowing both where you are and WHEN you are. Without accurate clocks, you can't determine your longitude. Today, without atomic clocks, our GPS devices would not be nearly as accurate as they are.

[Avbac23 · Rating 5 out of 5]

One of my favorite books, Dava Sobel's Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time, details John Harrison's lifelong quest to invent a clock that could keep accurate time at sea, and enable mariners of the eighteenth century and beyond to navigate around the world. Johnston's Time and Navigation: The Untold Story of Getting from Here to There "zooms out" from Harrison's story and gives a more complete history of those who came before and after Harrison, sharing in his vision and passions.

As a fan of the history of science and technology, I have long been amazed by just how many developments have been predicated on asking the two simple questions, "what time is it?" and "where are we?" So when I took a trip to Washington, DC a few years ago and discovered the museum exhibition that this book documents at the National Air and Space Museum, I was excited: "they made an entire exhibition just for me!" So naturally I had to buy the book. I've flipped through the book a few times since, but now that I've finished reading it cover-to-cover for the first time, I recall the fun I had browsing through the museum and marveling at what these timekeeping and navigational technologies might enable next.

A special treat for me has been reading astronaut Michael Collins's memoir, Carrying the Fire, in parallel with reading this book: as I've read in this book about the extension of terrestrial navigation techniques into space, Collins's book has described how he used those techniques to get the Apollo 11 mission safely to the moon. These two excellent books give context to each other, and tell two complementary stories that delight fans of space flight and navigational technology.

An aspect of navigation that isn't covered in Time and Navigation is the crowd-sourcing of map updates through projects like openstreetmap.org. It is exciting to think about what lies ahead, not just in the refinement of satellite-based and ground-based radio navigation, but also in conveying information about the earth, like updating new routes and points of interest, by collaborating and developing community ties with occasional, hobbyist, and professional mapmakers around the world. Can we address privacy concerns by taking, for example, real-time traffic updates out of the hands of individual privacy-infringing corporations, and establishing pseudonymous open-source travel-time databases instead? Might such open-source projects encourage contributions through reputation scoring and gamification? These aspects are opportunities for advancement that may one day warrant a new chapter in written histories of Time and Navigation.

[Cade · Rating 3 out of 5]

This book is a just OK book on a very interesting topic. I saw the exhibit at the Smithsonian Air and Space Museum for which this book was written. However, due to my interest in this topic, I was already aware of the most pertinent and interesting bits presented here. This book does not go into great depth on any of the topics presented.

[Kursad Albayraktaroglu · Rating 4 out of 5]

Excellent book covering the history of time keeping and navigation technology through the ages. I found the chapters on the early days of aerial navigation and the genesis of satellite navigation particularly interesting.

[Stan McQueen · Rating 2 out of 5]

From the description I thought it would be a more technical treatment but it's very elementary. Probably suited for someone who is just now learning about navigation, but I already knew too much to make this book interesting.

[John_g · Rating 2 out of 5]

Doesn't help understand how to navigate.
Math should be emphasized with clear diagrams but lost in blurry, historical drawings.

[Margaret Fritts-DeLuca · Rating 3 out of 5]

Maybe a good beginner's book, but too scattered for my interests.

[Roger Rosenberg · Rating 4 out of 5]

Really enjoyed the book. Having used celestial to navigate aircraft over the Pacific, I am amazed at how fast the technology developed. Good summary of the science of navigation!

[Marc E · Rating 4 out of 5]

I found this book a good overview of topic. Easy enough to read to older kids but detailed enough to generate a broad curiosity for those scientifically inclined. I found it an easy read as each chapter is a topic to itself; and while each chapter builds upon the previous one - for me it was not a book to read cover to cover in one sitting.

[Mary · Rating 3 out of 5]

Disappointing. More descriptive of how time and maps changed over history then explaining the how's and whys of the changes.

[Lexish · Rating 3 out of 5]

I loved seeing the old navigation equipment/maps and reading how they developed over time. I was less interested in the modern-day technology, actually.