Use of Celestial Navigation Today

If there is a world-wide GPS outage the positoning part is small potatoes compared to the loss of the timing function. Is my understanding anyway. No internet, not cell phone, no wire transfers etc.

I believe so, and catastrophic failure of the systems we rely on daily may not necessarily be the result of attacks from malevolent actors:

Even the basic compass can be knocked out. This from 1882:


Can you put it in emojis for the next generation? :rofl::sleeping::innocent::thinking::crossed_fingers:t2::cold_face:

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Read this and shiver. This is bound to happen sometime but nobody knows when.

If a Carrington Event happened today, the world would likely have to deal with the simultaneous loss of GPS, cell phone reception, and much of the power grid. The global aircraft fleet might have to coordinate an unprecedented mass grounding without satellite guidance. Unguarded electronic infrastructure could fail outright.

If I am not mistaken to a large extent this discussion is about maintaining a degree a proficiency in what has become a “backup system”.

Ships today still have magnetic compasses. How often are they used to steer and maintain a course? Many years ago after departing Kaohsiung and heading south we experienced a power interruption that tripped the gyro-compasses. Until they were restarted, settled out and deemed reliable to use it was hand steering and magnetic compass.

I believe they would be rendered useless in the event described above, at least temporarily.

That’s how I see it.

There is a second argument that two methods must be used at all times. That would be a technical question about the nature of GPS and how it is used in ECDIS.


Back to basics, stuff that we learned with the boyscouts for the Navigator insignia. If you have an electronic watch dump it and ask next time as a birthday present a mechanical watch. However, it could well be that the mechanical parts inside are welded together by the sun flares energy. If all is lost try the sextant.

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I don’t know if you (@Kennebec_Captain) ever experienced this departing Guam but on occasion our GPS would become erratic for several hours. When it happened on successive trips in the same general area after leaving Guam the discussion between the mates was that the navy was playing games with us.

Been to Guam a few times, didn’t see that.

I can recall two times having trouble with a Sat system. Once in the Gulf of Thailand some problem with the SATNAV. I was third mate. Capt had me do a LAN. Chief mate watched over one shoulder and captain over the other while I worked it out and plotted it.

The other time was an early GPS, it switched over to DR but no alarm. Still in radar range so it had me scratching my head for a while till I noticed the tiny letters “DR” in the corner of the screen.

When I was sailing, I found the Casio analog-digital watch just perfect to find out where the North or the time was …


When I became pilot, I just bought a cheap watch to know which day it was …



I kind of like it, tbh, but most Rotterdam is a pretty… “industrial” place from my trips through there. This has got some pizzazz!

This “compass” works perfectly… if the watch shows noon at the true local noon.

The Equation of Time is not the problem, through the year the difference is only about ±15 minutes.

The time zones (and in addition the daylight time) matter much more:
From Cape Finisterre, the westernmost point of Spain, to Otranto, the Italian side of the entry into the Adriatic Sea, or to the eastern part of Hungary, the true local noon varies by two hours in the same time zone.
In higher latitudes, this is extreme: Inside Norway alone; the true noon varies by nearly two hours


A post was split to a new topic: Opinion | Ditch the GPS. It’s ruining your brain. - WP

It’s possible in navigation theory to get deep in the weeds. To help guys like us that have to solve problems on a practical level rules of thumb are used. Like the fix in the middle of the triangle. Simple and close enough.

We’ve heard don’t rely on any single aid, particularly a floating aid a million times. GPS is a different kettle of fish however. Can’t be evaluated with simple rules.

With sophisticated systems using independent verification used in the offshore industry it is impossible to spoof the GPS signal and have it pass unnoticed. If the GPS signals disappeared altogether world wide it may be a good time to pucker up and kiss your fufu valve goodbye because nothing good is happening.
If knowledge is allowed to pass from the instructor to pupil without rigour then that knowledge slowly degrades. We need the instructor to get among the weeds to lift and maintain the standards and it is not just in Navigation. There has been catastrophic failures in the operation of the main engine of a large container ship and serious damage to the switch board of a cruise ship that I’m aware of. Both cases had the senior officers who commissioned the vessel having been relieved by other officers and then these officers passing the knowledge down to others until it became like Chinese whispers and vital information was lost.


Yes, well put. I thought this tread: Interesting Article - How Technology Grows was relevant to marine engineering in the sense of having deep understanding vs work-a-day knowledge.

When I was sailing international in the 1970’s & 1980’s, I would sometimes come across a ship in the middle of the ocean flashing some kind of Morse Code at me. I have never been able to remember Morse Code so I would simply call on VHF 16 and ask them what they want. It was always somebody just wanting to practice.

I was once part of a riding crew on a tug being towed by an AHTS from Morgan City to Bombay, India. I would perform my Cel Nav every day & night and then compare my position to the position obtained by the AHTS’s Captain, a retired US Navy Commander. We usually got between 5 to 10 miles within each other, sometimes a little closer. Keep in mind that we were separated by only 1,800 feet of tow wire!