Roughly a year per sign — the most useful clock in the chart.
Jupiter spends close to twelve months in each sign, which makes it a practical marker of birth year. Anyone who knows the sequence can date a chart to within a year or so from Jupiter alone.
It ruled Pisces as well as Sagittarius before Neptune was found in 1846. The pairing is structurally neat: both are mutable, and they sit opposite each other.
At about a quarter of a degree a day at its fastest, Jupiter is where the outer planets begin — bodies whose position says more about when someone was born than about the hour.
What it is
The largest planet — more massive than everything else orbiting the Sun combined.