I was in the last class to have the old celestial navigation class. It's not a difficult thing to do. You take a measurement with a sextant then consult a fifty pound book full of tables, get the two closest numbers to what you want and interpolate.<p>There are various techniques based on time of day and the stars you can see, but if you're not doing it regularly you're going to have to look up the procedure anyway.<p>And although you might not always be able to rely on GPS, inertial navigation, dead reckoning, and visual navigation using landmarks, celestial navigation has a huge drawback.<p>It's defeated by cloud cover and fog.
Three hours of training? Either celestial navigation is much easier than i think it is or this is exactly the sort of compromise mothers should warn their children about. I'd rather sail into a GPS outage with a one in ten chance of having a navigator trained 30 hours on board than with a 100% chance of having one trained three. And it gets better when you consider crews larger than one. Sure, we all know that decision making isn't easy, but that should not be an excuse to get away with a compromise like that.
This topic, though a different article, received a fair bit of discussion a month ago:<p><a href="https://news.ycombinator.com/item?id=10385244" rel="nofollow">https://news.ycombinator.com/item?id=10385244</a>
Why not instead a "modern" digital sextant consisting of a digital camera and software. Still enables navigation by the stars (or sun) as a backup to GPS without having to spend thousands of man-hours training cadets to do it manually. And while not as accurate as GPS certainly, it would most likely be better than or at least equal to the best human navigators.<p>You'd harden the system against EMP which is probably a standard requirement of military electronics anyway (I'd hope...)
Even if you don't encounter an enemy attack that disables GPS (which is not difficult), you (meaning anyone concerned with national security) should still be prepared for navigation by alternate methods when you consider how often equipment malfunctions can cause self-jamming of GPS. It's happened to me on systems that I support.
Interesting. I've been reading the Aubrey-Maturin series by Patrick O'Brian, and besides looking up what in the world spotted-dog, calipash, staysails, the various and sundry varieties of vessels, or a Magellan jacket are, there's a fair amount of old-time celestial navigation throughout - the constantly documented daily ritual aboard ship is punctuated by the daily observation of noon, and comments on the nutation(?) of the planets... It's pretty amazing how well people were able to fix their positions with such primitive instruments.<p>I can pick out the Big Dipper at night, and figure out if I'm going east or west by the sun during the day, but that's pretty much the extent of it. I've never been out in the open sea, where I imagine you can actually see the stars well - the day-glo murk from the omnipresent streetlights blots out most of them if you are anywhere near civilization.
I must be the last person ever who survived thanx to sextant in 1990:<p>I had $50 plastic sextant "Ebco". I made a program in my pocket computer (Atari Portfolio) which automatically showed your position on a map (A line perpendicular to the sun, ie with several measurements you could get a total fix). Realized however that sextant is useless if there is no horizon visible in direction of the sun. I needed "artificial horizon" but it was $1000. Too expensive. Then I saw the movie about Nansen crossing the Greenland. All he had was a bottle of mercury. He simply measured the angle between the sun and its reflection. I felt soo stupid.<p>Then I started paddling from Vancouver city to the west in 1990. I did not understand them tides. I did not know you can get pretabulated tables. I was paddling against tides most of the time. Somewhere between Kelsey Bay and Telegraph Cove there was 2 weeks period of fog and rain. I totally lost it. I was running out of food. I decided to turn back to Kelsey. But then the setting sun peaked out and I was able get my longitude. I was 3 kilometers from Telegraph cove. Paddling back would have been a suicide.<p>About 80 km between those places. But I was doing it against tides averaging less than 10 km per day.<p>BTW. George Vancouver was also stuck for weeks at the same stretch of Johnstone Strait. The devilish tide current appeared to be totally random and followed none of the god-given rules and laws.<p><a href="https://www.flickr.com/photos/timonoko/9513772987/in/album-72157634483451516/" rel="nofollow">https://www.flickr.com/photos/timonoko/9513772987/in/album-7...</a>
We will be seeing more of this kind of stuff as the world gets more complicated. Obviously, there are not enough people who know how to troubleshoot computer networks, debug poorly written legacy code and simply maintain the complex realtime systems that are used to automate buildings, boats and planes. I can imagine pilots will continue to be required on planes for this reason even though planes largely can fly themselves. Same thing with reading topo maps - a skill that all infantry will continue to need even though they have gps. In a sense, this is insurance needed to protect us from "the ghosts of Luddites'.
If anyone has read "Ghost Fleet", this seems appropriate. However, I tend to agree with usrusr about the seemingly shallow depth of the course.<p><a href="http://www.amazon.com/Ghost-Fleet-Novel-Next-World/dp/0544142845" rel="nofollow">http://www.amazon.com/Ghost-Fleet-Novel-Next-World/dp/054414...</a>
> The same techniques guided ancient Polynesians in the open Pacific and led Sir Ernest Shackleton to remote Antarctica, then oriented astronauts when the Apollo 12 was disabled by lightning, the techniques of celestial navigation.<p>You'd think the proof reader would at least catch an issue in the very first sentence.
Very cool.<p>Back in the 1970s I owned a sextant that I kept on my sailboat but I don't remember how to use one anymore. GPS is great but old skills like celestial navigation and old fashioned dead reckoning get forgotten.