What is the chart ruler?
The planet that rules your rising sign. The tradition reads it as the planet that steers the whole chart: its sign says how you go about things, its house says where your life tends to happen, and its aspects carry more weight than the same aspects to any other planet. It is the thing a working astrologer looks at right after the Sun, Moon and rising, and the thing most apps never mention.
Where astrologers disagree
Nine signs have one ruler everyone agrees on. Scorpio, Aquarius and Pisces have two: the traditional ruler (Mars, Saturn, Jupiter) and the modern one given after the outer planets were found (Pluto, Uranus, Neptune). Both are shown where it applies.
Where you see this in OrbHeaven
Your own chart is calculated from your birth details, and this definition is written out again there with your numbers in it rather than in the abstract. The chart, the glossary and thirty days of dated timeline are free, and nothing here is charged per question.
About a minute. Birth time optional, and no account until after you have seen it.
The chart
What the picture is, and what the numbers on it are measuring.