Is the constellation book really credible? How credible is it?

It varies from person to person. Even if an analysis feels like it, there is a reason. If you don't like it, there is no need to force yourself to believe, and there is no reason to change yourself. But I think there will always be a small number of people like everyone else in the analysis, so a large number of people choose to believe it. Our attitude is, in the entertainment circle with a grain of salt ~ hehe.