HOW DID ANCIENTS KNOW & CALCULATE THE EQUINOX

[r6r6]

Originally Posted by BigJohn

Without a time piece, how do you find the longest and shortest day?
Besides, how did they realize the hours of day light were not the same every day?
For me, it is a very difficult question.

Sundials? Ergo shadow movement

[BigJohn]

Originally Posted by Legrand

No more power at my home. So I’m writing from cell.

No need of time to find it. Simply observe from the same point of observation in a year where the sun sets. On a circle where you are the center, put a rock where it sets the most far away on one side at the beginning of winter and put another rock on that circle where it sets down the most far away on the other side, which marks the beginning of summer. When the sun sets in the middle of those two rocks you have the equinox.

SOUNDS REASONABLE!
But how would one realize this data is important?
For example, at the Equinox, the amount of daylight and darkness at these 2 days per year are the same.

Originally Posted by BigJohn

SOUNDS REASONABLE!
But how would one realize this data is important?
For example, at the Equinox, the amount of daylight and darkness at these 2 days per year are the same.

Just like for the birds who need to migrate when the seasons change to find food or not die from the cold of winter, even as nomads in the last ice age the change of seasons must of been remarked in order to survive. And latter to need to know when to plant the seeds in spring. To know and find out pointers to indicate when the seasons change was thus a matter of survival for us then.

My two cents...

[r6r6]

Originally Posted by Legrand

My two cents...

Position of sun, moon stars etc relates to seasonal changes.

[BigJohn]

Originally Posted by r6r6r

Position of sun, moon stars etc relates to seasonal changes.

How does the position of the Sun, Moon, Stars, etc. have any bearing as to how the ancients could tell some days were longer then other days without a reliable time piece?

[muffin]

Originally Posted by BigJohn

Sounds like a simple problem. but how did the ancients know and calculate the equinox without reliable time pieces?

Good afternoon BigJohn

Do you think this is the first time around

[r6r6]

Originally Posted by BigJohn

How does the position of the Sun, Moon, Stars, etc. have any bearing as to how the ancients could tell some days were longer then other days without a reliable time piece?

Not with Boolean math-magics is my best guess.

[BigJohn]

Originally Posted by Legrand

Hello Big John,

One thing if for sure, when the Egyptians build their first Pyramids, around 3500 BC, they already new the exact position of the equinox in a way that even today we would have difficulty to build a so huge construction that is perfectly aligned with the True East and West line as the pyramids are.

On the equinox day the sun sets on the true West and the sun rises on the True East. Drawing a line from those two points at that time of the year gives a good idea of the direction for the true East/West line. Finding the place where the sun sets on the Equinox in those times is the only way I know of to find that line. Yet the finding with such precision the angle of that line in the way the pyramids where build would be a challenge for any surveyor and builders of today with all the tools we have.

As for realising that the time of day = the times of the night on the equinox day. Don't know how they did it, and when we realized it was such a thing on the equinox day.

The oldest sun clock dates from around 1500 BC. But then it only gives the time during the daylight. How did they calculate the time during the night time to compare with day time? Most probably from observation of the movement of the stars. But this is only speculation from my part.

Even more fascinating than the equinox, is the knowledge they had in those times, as shows for example the Mayan calender, of the north/sud pole axis of rotation of the earth doing a precessional circle in the sky that takes 25 920 years. It's from this movement of the axe of rotation of the planet that we say that we are entering the age of Aquarius that will last for about 2160 years.

Have a great day!

Your method of finding the equinox seems the most probable. Where I live,
Apaches knew about the equinox probably via the same method as you have mentioned.

What I suspect the ancients used to measure time was some form of water clock. Knowing when the sun is directly above,
a cylinder could be filled with water with a small whole in the bottom. After much trial and error, they would know how
much water would be needed in the cylinder so as to leak out of the cylinder from high noon to the next high noon.

The Babylonians used a base 10 and base 60 number system. The base 60 number system probably came about because of trade.
12 played an important part in their number system. Before they had mastered how to measure time, they
probably believed the length of daylight and darkness was probably of equal length.

With a calibrated water tower calibrated for 1 day, they could easily divide the height of the water in the
water clock into 24 equal parts. With a base 60 number system, they could possibly
calibrate the water tower down to the minute.

[r6r6]

Originally Posted by BigJohn

How does the position of the Sun, Moon, Stars, etc. have any bearing as to how the ancients could tell some days were longer then other days without a reliable time piece?

Sundial if not others for reliability.

Modern Scientist know that the height of the largest tetrahedron we know to exist in Universe that is on Mars. The know because of the shadow length and other data.

Sundials use shadows.

[BigJohn]

As already discussed several times, how can a sundial be used after the sun 'sits'?