The MUL.APIN series of astronomical tablets
- now found in the British Museum -
describe a UNIQUE heaven which occurred
at ca. 2340 BC, plus or minus 20 years.
See Werner Papke, Die Sterne von Babylon, "The Stars of Babylon".
See Tablet 1 - The path of EnLil - of MUL.APIN.

MUL.MUL (eta-Tauri,the Pleiades) and GIR.TAB (beta-Scorpii)
were visible at the East and West points of the horizon and also
defined the Vernal and Autumnal Equinoxes.
The equator, ecliptic and horizon cut the Equinoxes exactly,
with alpha-Leonis and iota-Aquarii at the Solstices.
It was a "heavenly fit" for ancient astronomers.

More than that, delta-Ursae maioris was not only at the
lower culmination on the meridian in the northern sky (2360 BC)
but also exactly on a line connecting the celestial north pole
with the Solstices - an "absolute" position
irrespective of the position of the observer on earth.

THE CARDINAL DIRECTIONS
OF HEAVEN WERE FIXED
Hebrew QEVI'A  = KHUFU, CHEOPS
(Hebrew Qevi'a means "calendric fixing")

Using a gnomon as described in the Old Indic Katyayana-Sulbasutra
the ecliptic could be "fixed" in ca. 2340 BC point for point
relative to the fixed stars and cardinal directions.
This was the beginning of formal astronomy.

1.
The Path of
EnLil

is the "upper" heavenly path of the rotating stars,
north of +16.69 degrees declination

2.
The Path of
Anu

is the middle "normal" heavenly path
along the ecliptic, which is the path of the Sun

3.
The Path of
Ea

is the "lower" path,
Papke calls it the path of the water,
the path of stars below the ecliptic

EnLil
Latvian JANU.LIELais
upper elevated path of Anu

Anu
Latvian JANU or JUMU
Heaven, Ceiling

Ea (E.AN.NA)
Latvian JANU LEJINA
lower path of Anu