How to know the ecliptic from my location ?

[medwatt]

Hello,

I'm trying to understand the whole motion of the stars in the sky but I'm stuck at the concept of the ecliptic. I want to be able to really convince myself that the ecliptic is 23.5 deg inclined to the equator by just studying the Sun during daytime. I read somewhere that the ancients plotted the ecliptic long before the even knew that the Earth revolved around the sun. What exactly did they plot ? I know that the major planaets and the moon are not far from the ecliptic but thats because I've seen the maths. I want to be able to deduce the the same thing the ancients did. So here are few of things I might have observed assuming that I'm at the equator:

1. Today is March 21. I noticed that the sun rose from exactly the eastern point and set exactly west. I also noticed that the sun passed my zenith around midday.

2. From March 21 to June 21, I notice the sun rising more towards the north everyday and getting further away from the zenith.

3. From June 21 ro September 21, I notice that the sun's movement seems to be reversing and getting higher every day. On Sep 21 the  sun's path  is exactly as it was on March 21.

4. From Sep 21 ro Dec 21, I observe the the same movement of the sun as was during March 21 to June 21 except that the sun is moving southwards.

5. And so on . . .

Every day I plot the motion of the sun on my sky such as in: [someone in the northen hemisphere]

The question is, now that I'm equipped with all these details:

1. How can I plot the ecliptic just as the ancient did so that I can be able to locate the planets at night.

2. From just staying at my location and knowing that the earth was spherical, would I be able to draw this picture:

3. Because of our understanding today, the ecliptic is as is depicted above. What ecliptic did the ancients actual plotted ?

Thanks !

[acey]

See here:

http://onlinelibrary.wiley.com/doi/10.1111/j.1600-0498.1969.tb00132.x/abstract

Also here:

http://articles.adsabs.harvard.edu//full/2002JHA....33...15J/0000015.000.html

[Steve Ward]

The ancients plotted the actual Ecliptic exactly as you did , by careful observation ... the articles referred to above show how they calculated the 'obliquity' , i.e. the relationship between the Ecliptic and the Celestial Equator.