Egypt produced one of the earliest working systems for telling the time at night, and most of it can no longer be read. The decans are thirty-six star groups whose successive risings divided the night into hours, listed on coffin lids from the First Intermediate Period onward as tables of which decan rises in which ten-day period.
The tables survive in quantity. The identifications do not. Beyond Sah and Sopdet, and a few probable matches, nobody can say with confidence which modern stars most decan names refer to, and the reconstructions disagree. Precession has moved everything, the lists were copied for centuries after they stopped being observationally current, and the names are descriptive in ways that do not narrow things down.
That is a useful corrective to how ancient astronomy is often presented. A civilisation can run an accurate practical system for two thousand years, write it down repeatedly, and still leave a record that cannot be decoded, because what was written was the operating table rather than the observations behind it.
The decans had a long afterlife regardless. They pass into Hellenistic astrology as the thirty-six decans of the zodiac, ten degrees each, and from there into the medieval and modern Western tradition, where they are still in use and are still called decans, in a system that has nothing to do with telling the hours of an Egyptian night.