Will there be exactly the same constellation at different times? For example, in the Ming Dynasty, would someone's astrolabe be exactly the same as mine?

I think there is. Theoretically, the astrolabe has two constellations: Sun, Mars, Neptune, Moon, Jupiter, Pluto, Mercury, Saturn, Rising Venus, Uranus and 12. Of course, if you count the angle, the more detailed the arrangement, the more kinds, but even astronomy, there are fixed numbers (that is, various astrolabes). But time keeps going, infinitely multiplied by 365. As long as it doesn't reach the end of the world, time will definitely go on. So, sooner or later, I will meet two people with identical astrolabes. This possibility may be small enough to meet two people with identical looks and fingerprints on earth, but it will definitely happen.