Because the division was made into equal arcs, 30º each, they constituted an ideal system of reference for making predictions about a planet's longitude. However, Babylonian techniques of observational measurements were in a rudimentary stage of evolution and it is unclear whether they had techniques to define in a precise way the boundary lines between the zodiacal signs in the sky.[8] Thus, the need to use stars close to the ecliptic (±9º of latitude) as a set of observational reference points to help positioning a planet within this ecliptic coordinate system.[9] Constellations were given the names of the signs and asterisms could be connected in a way that would resemble the sign's name. Therefore, in spite of its conceptual origin, the Babylonian zodiac became sidereal.[10]