How the ancients navigated

[Byrd]

 I think the Great Pyramid was the major marker not quite at the 23.5 parallel but near enough it might even have had been the summer solstice marker when it was constructed for the purpose of this example.
 The technique is simple enough, and rests on the fact that the suns ground position changes by about a degree each day which is sixty nautical miles. The Sun at the solstices reaches 23.5 degrees north in the northern hemisphere and the same in the southern hemisphere at roughly the tropic of Capricorn. This method requires a static marker like the known position of the GP or in modern times a place on the map or chart. I will give a practical example.
 Say I am in the Western Pacific Ocean on the day of the summer solstice, I know that the suns ground position for that day tracks the 23.5 degrees south line of latitude. Thats as far south as the sun goes south. I look on the Chart and notice that if the suns ground position went down to Sydney. Then it would be... off the top of my head about fifteen days sun distances from Sydney to the 23.5 line of lattitude. I draw a line on the chart from Sydney up to the 23.5 lattitude line,and wait for the sunset that day,In modern times I go out on deck and as the last glimmer of the setting sun shines over the horizon I take a compass bearing of it, Knowing that Sydney is fifteen sun positins south of it , the compass will read approximately fifteen degrees less, so I note the two compass results, and draw the lines on my chart and triangulate my position on the ocean. In Ancient times a hinged stick would do the same thing. Not as precise as present day GPS but with a skillful operator a feasible way to draw a map or chart Islands, without an accurate chronometer.

Firstly, the Great Pyramid isn't visible at a range of three miles (too small, and at 3 miles the curvature of the earth comes into play.)

Second, why use the GP at all?  You could use a coastal mountain (volcano) that you might be able to see for 4 or 5 miles... and that's inefficient because measuring distance on the water isn't as easy as it is measuring it on land.  The big Tahitian canoes travel at a rate of about 3-6 miles per hour (depending on the wind), and it's very hard to tell the shift in the sun's position if you've only traveled 20-30 miles.

[annonentity]

Because it could be used as the primary latitude marker ,in a known place from which all other reference points could be compared to .If you were in the western ocean, you would use dawn, to get an angle. This would act as the Sydney in my example. Once you have the angle of the sunrise or sunset. It would remain essentially the same for all practical purposes, if the Earth was flat the angle would change as the suns subpolar point would cause it to contract as it moved. as it moved further away from you...but as the Earth is a Sphere it would essentially be the same as it moved over the straight northern point in the line up from Sydney. on the 23.5 meridian. Since you know the distance from Sydney to the tropic of capricorn line for that day, you have a distance and two fixed points to do a triangulation. In those days they were mapping and charting and fixed known points would be  scarce.
 So to use an analogy, it is like having a laser light shooting vertically up into space from the two locations,and since they are known positions you can triangulate between then to get another known fixed point. As sixty nautical miles is one degree on the earths surface,You know the degrees from the sunset point to Sydney or the GP ..or the whatever.

[Sirius]

With the stars and their eyeballs. The problem is looking at ancients with modern eyes. With modern eyes you have light pollution and sleep when it's dark or otherwise live indoors. You never use your peripheral vision.

There are not that many stars, what is stars and what is not and how they move is easy to discern and learn. The mysteries around the stars started because it was in our eyeballs every night and fantasy is our jam. Nothing complicated and we can't have that.

The stars and their movements are little compared to what you navigate in every day life today. The ancients where not blind walking into trees and drowning all the time (well some did I mean RIP, thank you for the sacrifice)

One benefit I have from spending an inordinate amount of time moving in ALL directions is that, yup, you can see the distance to Venus at dusk. I love watching the sunset with Venus shining bright and think about just floating there straight ahead. It's 100% possible to triangulate with the stars and planets. The night sky is not a 2D backdrop and you can see it if you train your vision.

Hubris condemns us to think we are smarter than our ancestors when all they did where simple things

[annonentity]

Yes they were simple things and simple people without the gadgets. So the tools would have been in their head's life was short and schools scarce, I think we have greatly underestimated them.

[Sirius]

Yes they were simple things and simple people without the gadgets. So the tools would have been in their head's life was short and schools scarce, I think we have greatly underestimated them.

They had gadgets, somethings in life are mundane and not recorded. Farmers almanacs, merchant slips etc. is good source of history imo without politics. Trade secrets are not written down in guilds or closely guarded. I wouldn't be surprised if ancient navigators where in a guild. There are also other fun angles like magnetoreception and seeing field lines...ley lines and things.  We don't observe closely, we live in boxes and navigate cities, who knows what they saw in the wind and through just observing nature.

[Nerb]

  It was longitude which was the difficult one to do . As there had to be an element of time involved.

What if those seafarers used something as simple as marked candles to mark time? Or a good old egg timer? Both or either could be well calibrated before leaving to have consistency over quite a distance.

Too simple?

[annonentity]

What if those seafarers used something as simple as marked candles to mark time? Or a good old egg timer? Both or either could be well calibrated before leaving to have consistency over quite a distance.

Too simple?

If you had a globe with way points that were say the temple structures on the Canaries or the Azores or Easter  Island and the prime meridian was the GP. All you would need is to know the day of the year and the latitude of the suns ground position on that day. If you were travelling East The tip of sunrise would tell you the latitude line, and if you knew that the GP was six hundred miles north of the line that day you just headed ten degrees north of the suns rising position, since one degree on the earth's surface is sixty nautical miles. You could take your angle from the suns rising position and plot a line six hundred miles south of the GP and get a position. Within a few miles for all practice purposes. Since magnetite was mentioned in writings about 200 bc you could hold a compass course.
 I ran a simulation with chat GP and asked it , if I set sail on the day of the Southern solstice from my home port and wanted to go to Brisbane and I headed three degrees south of the setting sun and made course adjustments as the sun went north, How far off would I have been , It said a hundred miles That was doing it by guesstimate using an extended pinky as one degree..  But it needed someone to have first mapped the way points on the globe, Unless you were just exploring and finding a place  then you would have to set of some structure to know what day it was with regards to the solstice to find your way back to base. Or the way points already mapped.

[Sirius]

What if those seafarers used something as simple as marked candles to mark time? Or a good old egg timer? Both or either could be well calibrated before leaving to have consistency over quite a distance.

Too simple?

the night sky is a clock.

[annonentity]

and your brain is a computer that few people know how to use.

[Sirius]

and your brain is a computer that few people know how to use.

not a computer, consider everything you know is learned through a 2D lens. The topic is navigation. If you go to 3D you are still stationary, if you move into time your swimming in the current. Orthogonal projections is key when it comes to geometry