Question

in the astronomical sense what is the celestial equator and what is the meridian? Please make this easy to understand

Answer 1

Imagine that all the stars in the sky are attached to a transparent sphere(the Celestial Sphere) with the Earth at its center, and that this sphere spins around an axis that
lines up with the Earth's North and South poles. The points that lie directly above the Earth's equator on the Celestial sphere are on the Celestial Equator. In effect the Celestial equator divides the Celestaial sphere into a Nothern and Southern half just like the Earth's equiator divides the Earth into a northern and southern half.