How many constellations are on a celestial sphere? How many ...

[formula1]

How many constellations are on a celestial sphere? How many boundaries are on a celestial sphere? Are boundaries unique to a constellation or shared?
 
  What will be an ideal response?

Question 2

What causes precession and why does it move the celestial equator among the stars?
 
  What will be an ideal response?

[rekilledagain]

Answer to Question 1

88 constellations, 88 boarders, shared

Answer to Question 2

Precession is caused by gravitational forces of the Moon and Sun acting on the equatorial bulge of the spinning Earth, causing the Earth's axis to sweep around in a conical motion. Because the celestial equator is defined by the Earth's equator, as the Earth precesses the celestial equator moves slowly against the background of stars.

[formula1]

TYSM

[yeungji]

Thanks for the timely response, appreciate it