The Sun
The Sun is one of the two luminaries, the light of the day chart and the center of the classical solar system as a living symbol. He does not retrograde. He does not borrow another body's light. In a birth chart the Sun describes conscious vitality, the style of will that wants to be known, authority of the heart, and the year as a story with a center. He is not the whole chart. He is the part that organizes a life around what it is trying to become in the open.
Traditional authors give the Sun the topics of honor, fathers in many older texts, gold, the eyes in some medical correspondences, and the king or the office of rule. This library keeps the symbolic list and leaves the medical correspondences on the shelf. A Sun placement describes a style of vitality. A diagnosis, a career outcome, and a parent's character are larger questions than one placement. If an older book says the Sun is the father, read that as one traditional signification among others, and let the whole chart answer.
The Sun rules Leo and only Leo. In that fixed fire sign he is in domicile, at home in a weather of radiance, creativity, and a center that can give. He is exalted in Aries, classically near 19 degrees, an honored guest at the start of the tropical year, where light and the power to begin agree. He is in detriment in Aquarius, opposite Leo, where the circle and the system ask the single heart to justify itself. He is in fall in Libra, opposite his exaltation, where the scales keep asking about the other person and the single will has a poorer fit. Detriment and fall are conditions of craft. They are not a judgment of the life.
In the traditional system of joys, the Sun rejoices in the ninth house, the place of god, far travel, and the counsel that comes from beyond the local street. Joy is a house preference, different from domicile. A Sun in the ninth is glad of the place. A Sun in Leo is glad of the sign. Both can be true, or neither, depending on the chart. The natural sign-and-house pair that shares the Sun's creative topics is the fifth house, Leo's house: children, pleasure, and the act of making.
Sect matters in traditional reading. The Sun is a diurnal planet, belonging to the day team with Jupiter and Saturn. In a chart cast for a daytime birth, the Sun is in sect, and his testimonies are easier to trust as straightforward. In a night chart he is out of sect, and the same placement can be more strained, more proud, or more in need of the Moon's cooperation. Sect is a modifier. It does not replace the sign and the aspects.
Read the Sun's sign, then his house if you have a birth time, then the aspects he makes to the Moon and the Ascendant ruler. A Sun square Saturn is a different sentence from a Sun trine Jupiter. The aspect is the conversation. The sign is the weather.
In practice, give the Sun one line: how this chart tries to be alive on purpose. Then let the Moon say what the body needs. For the domicile, read Leo. For the exaltation, read Aries. For the poorer fits, read Aquarius and Libra.