[Scimon]

 Celestial Navigation works by measuring the distance of Polaris to the horizon in Degrees. The measure you get corresponds with your latitude. If you measure 90 degrees you are at the north pole, if you measure 59 degrees you are at 59 degrees north. When done correctly celestial navigation can be extremely accurate, even more then so compasses. Celestial Navigation has been used since Ancient Greece with a huge degree of accuracy. Also as a side note you also have to take axial tilt into account but this was a extreme of simplification. The tools used, such as a sextant, for celestial navigation use the geometry of the round earth to work. When this is modeled on a flat earth, it gets a bit iffy. If you take a look at the attached image you will notice that 2 acute angles don't intersect the 90 degree angle at the same spot. In reality three people standing at 3 diffrent parts of the earth there line's of sight would intersect the same location.

[Humble B]

Celestial Navigation works by measuring the distance of Polaris to the horizon in Degrees. The measure you get corresponds with your latitude. If you measure 90 degrees you are at the north pole, if you measure 59 degrees you are at 59 degrees north. When done correctly celestial navigation can be extremely accurate, even more then so compasses. Celestial Navigation has been used since Ancient Greece with a huge degree of accuracy. Also as a side note you also have to take axial tilt into account but this was a extreme of simplification. The tools used, such as a sextant, for celestial navigation use the geometry of the round earth to work. When this is modeled on a flat earth, it gets a bit iffy. If you take a look at the attached image you will notice that 2 acute angles don't intersect the 90 degree angle at the same spot. In reality three people standing at 3 diffrent parts of the earth there line's of sight would intersect the same location.

Could this be an explanation why the information in FES' WIKI about navigation and Polaris is corrupted?

Q. What about other types of navigational instruments?

A. Using a compass, gyrocompass, or looking at Polaris as a reference for Eastwards or Westwards travel will take the navigator in a broad circle around the North Pole.

As a certified naval navigator myself, I can assure the readers of this thread that navigators do not use Polaris for "Eastwards or Westwards" navigation as the writer of the WIKI incorrectly claims, because since a couple of centuries we have a much better device for that: The Compass! (Magnetic or non-magnetic)

Polaris is only used by navigators to find their actual position on the ocean, by measuring the angle of Polaris above the northern horizon. But why the angle of Polaris is always equivalent to the latitude of the navigators position can only be explained with help of the globe earth model and a very far away Polaris, so I can imagine that the writers of the FES WIKI have a problem with educating their FE readers correctly about that.


Source: https://www.wikihow.com/Use-a-Sextant

[stack]

This assessment had a good explanation as to how the altitude of Polaris doesn’t work in FET:

"This is empirical evidence that anyone can validate for themselves by simply measuring the altitude of Polaris with a homemade clinometer and comparing the result to their latitude. If they match, you're on a curve. There is no theoretical distance above a flat earth where Polaris could be positioned that can mimic this relationship. It's impossible. A flat plane can't mimic a curve.”

http://debunkingflatearth.blogspot.com/2016/02/debunking-flat-earth-how-polaris-proves.html

[RonJ]

When I started learning to navigate using a sextant I had to also learn spherical trigonometry.  Standard flat surface trig just doesn't work when you are trying to find your position on earth using the elevation data you get with a sextant.  Makes you wonder just why that is.  Oh, you have to project the lines on a globe then use spherical trig to get a usable estimate of your actual position.  Try that using a flat earth model and see how fast you get lost while actually at sea. 

[Tom Bishop]

Q. What about other types of navigational instruments?

A. Using a compass, gyrocompass, or looking at Polaris as a reference for Eastwards or Westwards travel will take the navigator in a broad circle around the North Pole.

As a certified naval navigator myself, I can assure the readers of this thread that navigators do not use Polaris for "Eastwards or Westwards" navigation as the writer of the WIKI incorrectly claims, because since a couple of centuries we have a much better device for that: The Compass! (Magnetic or non-magnetic)

What you quoted already says compass, and uses the word "or" when using Polaris as a reference for Eastwards or Westwards travel. It appears that the Wiki is correct and should stay as it is.

Polaris is only used by navigators to find their actual position on the ocean, by measuring the angle of Polaris above the northern horizon.

That is all it can be used for? It is impossible to figure out where East and West are with Polaris?

But why the angle of Polaris is always equivalent to the latitude of the navigators position can only be explained with help of the globe earth model and a very far away Polaris, so I can imagine that the writers of the FES WIKI have a problem with educating their FE readers correctly about that.

From what I have read, all latitudes on earth were created based on Polaris.

We have left that part out because it is a topic for further study. We would need demonstration that the distances between latitudes are exactly equidistant, or that Polaris is exactly constant in its setting or rising as one travels North or South, which may or may not be the case. RE'ers do complain a lot about "refraction" changing the position of celestial bodies in significant ways.

[Humble B]

What you quoted already says compass, and uses the word "or" when using Polaris as a reference for Eastwards or Westwards travel. It appears that the Wiki is correct and should stay as it is.

No, the WIKI is not correct about navigation. Polaris is not used "as a reference for Eastwards or Westwards travel" (Unless the navigator has dropped his gyrocompass overboard, but that hardly happens)

Polaris is only used to find a ships location, because the number of degrees Polaris is visible above the horizon always matches the number of the latitude. If the ship is 57° North, than Polaris is visible 57° above the horizon, and when it is 32° North, Polaris is 32° above the horizon:



Wonder why that is not corrected in the WIKI

[stack]

From what I have read, all latitudes on earth were created based on Polaris.

I'm not so sure Polaris was the genesis.

"History of latitude measurements
The Greeks studied the results of the measurements of latitude by the explorer Pytheas who voyaged to Britain and beyond, as far as the Arctic Circle (observing the midnight sun), in 325 BC. They used several methods to measure latitude, including the height of the Sun above the horizon at midday, measured using a gnōmōn (a word that originally meant an interpreter or judge); the length of the day at the summer solstice, and the elevation of the Sun at winter solstice."

https://en.wikipedia.org/wiki/History_of_latitude_measurements

I can't find any reference to Polaris as the basis of 'latitude'. Not to say it isn't, but evidence as such is not extent.

[Humble B]

Polaris is only used by navigators to find their actual position on the ocean, by measuring the angle of Polaris above the northern horizon.

That is all it can be used for? It is impossible to figure out where East and West are with Polaris?

Because Polaris is always in the north it "can" be used for east - west navigation, but why should you use Polaris for that if the compass in front of your nose does a much better job for that.

But why the angle of Polaris is always equivalent to the latitude of the navigators position can only be explained with help of the globe earth model and a very far away Polaris, so I can imagine that the writers of the FES WIKI have a problem with educating their FE readers correctly about that.

From what I have read, all latitudes on earth were created based on Polaris.

By my knowledge the geographical coordinates were created based on the shape of the earth as a globe, because the cartographers who introduced it all used the globe as generally accepted model of the earth to be coordinated.

......or that Polaris is exactly constant in its setting or rising as one travels North or South, which may or may not be the case. RE'ers do complain a lot about "refraction" changing the position of celestial bodies in significant ways.

Polaris is constant in its setting and rising, because Polaris doesn't move. It is always fixed on the same location above the North Pole and never setts or rises. As long as you do not change your location, Polaris will always be visible in exact the same spot above the northern horizon. And as long as the light of Polaris enters the atmosphere in a steep angle, refraction is negligible. Only close to the equator where Polaris is close to the horizon refraction can change the angle a little.

[Humble B]

From what I have read, all latitudes on earth were created based on Polaris.

The latitudes on earth are based on the devision of a circle in 360°.
If you draw a line from the top of a circle towards the centre, and a line from the side to the centre, they will meet in an angle of 90°:

[Tom Bishop]

Polaris is only used by navigators to find their actual position on the ocean, by measuring the angle of Polaris above the northern horizon.

That is all it can be used for? It is impossible to figure out where East and West are with Polaris?

Because Polaris is always in the north it "can" be used for east - west navigation, but why should you use Polaris for that if the compass in front of your nose does a much better job for that.

Because compasses don't work everywhere on earth. At the latitude of Seattle, Washington, a normal compass is already scraping against the floor of its enclosure. It is actually only a narrow strip of land where the magnetic compass works, where the majority of the population lives.

See http://www.madsci.org/posts/archives/aug98/899130154.Es.r.html

So, what would happen to your compass as you walked north across Canada, towards the location of the North Magnetic Pole out on the Arctic ice? Well, here in Seattle the magnetic field is already tilting down into the ground, and I'm nowhere near the north pole. My compass still points north, but the needle is tilted, and the north end is almost scraping the bottom of the compass. If I started walking north, it would tilt more and more until it hit bottom and wouldn't work anymore.

We need a special compass in higher regions:

If I used a good, expensive compass, then the needle would be on a little axel and would not be able to tilt.

Even with such a special compass on an axel, at higher latitudes the magnetic field lines will becomes so vertical that 'gravity' takes over at a steep enough angle and it falls and becomes useless.

Polaris is constant in its setting and rising, because Polaris doesn't move. It is always fixed on the same location above the North Pole and never setts or rises. As long as you do not change your location, Polaris will always be visible in exact the same spot above the northern horizon. And as long as the light of Polaris enters the atmosphere in a steep angle, refraction is negligible. Only close to the equator where Polaris is close to the horizon refraction can change the angle a little.

Sure, but those are just words, not demonstration. We can't take 'common knowledge' for granted. In this scientific revolution of FET we must start knowledge afresh.

[Humble B]

Because compasses don't work everywhere on earth. At the latitude of Seattle, Washington, a normal compass is already scraping against the floor of its enclosure. It is actually only a narrow strip of land where the magnetic compass works, where the majority of the population lives.

Nowadays they use gyrocompasses, the work everywhere on the planet where ships can go, even on submarines in the deep sea. While Polaris is only visible on a clear night, not during daytime or a cloudy night.
And a navigator does not only want to know where the north is, he also wants to see as exactly as possible in which direction his ship is heading, and a compass shows that more precisely than a quick glance on Polaris. So why relying on Polaris for geographical directions if you have a compass?

Polaris is constant in its setting and rising, because Polaris doesn't move. It is always fixed on the same location above the North Pole and never setts or rises. As long as you do not change your location, Polaris will always be visible in exact the same spot above the northern horizon. And as long as the light of Polaris enters the atmosphere in a steep angle, refraction is negligible. Only close to the equator where Polaris is close to the horizon refraction can change the angle a little.

Sure, but those are just words, not demonstration. We can't take 'common knowledge' for granted.

This knowledge is "common" to mankind for at least 10,000 years, and confirmed by everyone who watched the night sky on the northern hemisphere.
But no one will stop you when you will check that by watching Polaris yourself.

In this scientific revolution of FET we must start knowledge afresh.

That's OK, but then you'll have still 10  centuries to go to catch up with mankind. Don't know if "revolution" is the right word for that, I would call that a "relapse".

[RonJ]

Early navigators could use Polaris to determine their latitude and their compass to proceed East or West, providing they were in the Northern Hemisphere.  What the compass didn't tell the navigators was just how far East or West they were, in other words, what was their longitude.  Such information could be critical to a sailor approaching the coast of California on their Easterly journey from China.  You needed a sextant sighting from other stars, a very accurate clock, and an ephemeris to obtain your longitude.  The first global sailors didn't have an accurate clock or ephemeris so just engaged in the procedure of  'running their Easting or Westing down'.  In other words the sailor would put the ship on the known latitude of their intended destination and proceed straight East or West until they found land.  When they were approaching the coast many indications were seen.  Clouds or land birds were some good indicators.  Some would even keep several land birds in a cage and release one if they thought they were near land.  A released land bird would fly up and circle the ship until it saw land and then proceed off in a straight line toward it.  Of course the 'birds eye view' was a bit farther at altitude because of the curvature of the earth and the sailors knew it and took advantage of that fact.   Today we don't need to do any of those things, but I have often seen shore birds on the container ship flying around and getting scraps of stuff laying around on the deck.  After we left the dock some would depart and fly off towards the shore.  Others would stick around too long and be trapped.  Usually they would die do to lack of fresh water.  Even today, modern sailors, and probably birds, believe in a global earth. 

[titidam]

Polaris is constant in its setting and rising, because Polaris doesn't move. It is always fixed on the same location above the North Pole and never setts or rises. As long as you do not change your location, Polaris will always be visible in exact the same spot above the northern horizon. And as long as the light of Polaris enters the atmosphere in a steep angle, refraction is negligible. Only close to the equator where Polaris is close to the horizon refraction can change the angle a little.

Sure, but those are just words, not demonstration. We can't take 'common knowledge' for granted. In this scientific revolution of FET we must start knowledge afresh.

So you've never looked at Polaris ?

[JCM]

Flat Earth theory has no explanation for why Polaris is lower and lower in the sky, eventually losing sight of it south of the equator. Almost as if something big is in the way of it. Meanwhile a southern polar axis point is coming up in the south becoming more and more visible as you travel south.  Zero explanations for this.  No round Earth math needed to see this.  It’s obvious geometry.  Not remotely possible on a flat Earth..

[RonJ]

That's easy.  Get yourself a good sextant and see for yourself.  If you start with a known position you will have an expected angle.  You will also have sextant corrections due to the bending of light at your specific latitude and your height of eye above the horizon.  Then, if you are way out at sea, and don't know your position, you can use these very same corrections to accurately determine your latitude.  Sailors know that this procedure works and is a demonstration not just words.  The safety of their cargo, and sometimes their very lives, depend on this 'common knowledge'.  Do you really think that they just take all this 'for granted'?