郑国渠如今还有吗:Navis.gr - Why Do You Need Celestial in these Days of GPS?

Why Do You NeedCelestial In These Days Of GPS?Notes provided with the compliments of Starpath School ofNavigation, Seattle, WASee also: 'Marine Navigation'

Well, the real answer is you don't. You don't even need aboat to get to Hawaii or Bermuda, or take a trip aroundthe world. You can do this by plane. It is faster,cheaper, and more comfortable.

On the other hand, if you do choose a life at sea, thenone of the fundamental rules of thumb that has beentested so many times we don't even have to go over it, isyou must be prepared to take care of yourself. You mustbe self reliant. Murphy's Law was invented on a smallboat at sea. Anything electrical is vulnerable after sometime in the salt air, especially when it is being jarred,bumped, banged, and dropped (i.e. going to weather).
Therefore we need some dependable means of navigation,and celestial is that. Needless to say, a hand-held GPSand spare batteries stuffed into a well protected vacuumsealed bag is a pretty good back up these days, but it isnot at all bullet proof. Furthermore, you are stilldependent on the availability of the signals. In any sortof worldwide military conflict, it is likely you wouldlose these, depending on where you were; you could losethe signals in a union dispute; it doesn't reallymatter... or as a result of a pre-commissioningvalidation exercise!

But quite beyond all of that (the numerical likelihood ofneeding it), learning celestial is still a most rewardingventure. It will make you a better navigator even oninland and coastal waters. You must, for example learnhow to do a running fix to do celestial and this couldwell pay off if you lost the GPS for some reason and wereleft with just one light shining through the fog; or youclose in on a coast, but can then only identify onefeature on the land (which is not a radar target), etc.Such problems are easily solved with a running fix.

Once you learn celestial, it is also a trivial matter tocheck your compass with the bearing to some celestialbody, even well away from any land marks and in a strongunknown current. You can't do this with GPS, nor anyother instrumentation on board, no matter what it cost,and no matter if you are a ship or a sail boat. The onlyway to truly check your compass at sea is with celestial.And if the boom hits your compass or lightning strikesnear by, or , much more likely, you simply realize thatit never was checked before, then this is something youmust do one day, etc....

And finally, there is a wonderful intellectualsatisfaction that comes from leaning and practicingcelestial navigation. It is a way to see science and mathreally come together and do something both tangible anduseful. Learning celestial will also make you a bettermariner because whether you show it or not, you will beanxious about your navigation if you are depending onsomething that you cannot hope to know anything about(i.e. GPS, it is a black box. You can just hope and praythat it works right... and you will only really know thaton the last day). And when you are anxious, you are morelikely to make a mistake.... and you risk the chance ofexposing your anxiety to the crew which could undermineyour leadership, which in turn could lead to all sorts ofunpleasantness...

In the long run, it's best to learn celestial, even ifyou are never going to use it. You will know you can ifyou need to, and that alone will make it worthwhile. Ifyou plan to crew on other vessels, then knowing celestialwill be an important part of your credentials and willcertainly help you find a good position.

And one last related thought: GPS is (in an abstractsense) just a version of SatNav (the Navy TransitSystem... now long gone) that happens to workefficiently. In short, we have had all-weather globalsatellite positioning for more than 20 years now. Yetthere never was any consideration at all by the USCG toremove the requirement of learning celestial from anocean license exam. And there is none now. Whatever thereasoning behind that decision, it is many-fold increasedfor small boats at sea.