Ghost Constellation

In astrology, there are twelve types of horoscopes. Among them, there is no "ghost sign". How can ghosts be associated with horoscopes? Since it can't, isn't the title "Ghost Constellations" not valid at all? Wait, wait, wait! If we are sure that there are ghosts after death, are so many ghosts (the number of ghosts is so large that it is impossible to estimate) still on earth or in the legendary "netherworld"? Of course it is in the "underworld". What is the meaning of the netherworld, just fro