Thousands of years ago, Indian priests recited a list of 27 star groups, the nakshatras, and tied them to rituals. Most people today file that list under religion.
'The Sky Keepers' argues it is something else: a record kept by careful sky-watchers to track time. The stars drift very slowly against the seasons, and the old texts hold clues that let us work out *when* they were written. You can check the dates with free star-map software and basic arithmetic. Every step is shown in the book.
It is a book about how an ancient science got filed in the wrong drawer, and what changes when you take it out.