Leo rises in the east at different times. What is the reason for meeting a star and the sun at different times?

As the earth's rotation speed gradually slows down, the sidereal day and the solar day are prolonged. Although they are all prolonged, the difference between them has changed. In ancient times, it was not 3 minutes and 56 seconds. And this difference is the value that affects the rendezvous time between the star and the sun. Because of this, at a fixed time every day, the star we see deviates from the celestial sphere by about 1 degree compared with the previous day, and the change of this difference will inevitably affect the change of rendezvous time. Then, according to the change of the rendezvous time and the change of the revolution speed of the earth's rotation, we can determine when it was built by mathematical methods and reverse calculation.

Do your best, I don't know if it's right.