The Sun, Moon and eight planets are the cast of your birth chart. Each one plays a role. Explore what every planet means.
Each planet is a department of life. The Sun is identity and purpose; the Moon is emotion and need; Mercury is thinking and speech; Venus is attraction and value; Mars is drive and conflict; Jupiter is growth and belief; Saturn is structure and limit; Uranus is disruption and freedom; Neptune is imagination and dissolution; Pluto is power and transformation. When a planet is emphasised in a chart, that department becomes a main theme of the life.
A placement is always read as a sentence: planet (what), sign (how), house (where). Mars in Aries in the seventh house is not the same as Mars in Aries in the first — same drive, different arena. Learn the ten planet meanings first, then layer the sign, then the house. The sign layer is expanded in planets in signs; the timing layer — when a planet appears to reverse — is in planet retrogrades.
Yes — astrology never adopted the 2006 reclassification, because astrologers work with symbolic meaning rather than astronomical classification. Pluto is treated as one of the ten main bodies, and its slow four-to-five-month retrograde is followed closely by the astrological community.
Technically the Sun and Moon are not planets: they are luminaries, the two lights. In practice astrologers say "planet" as shorthand for all ten bodies, which is why you will see the Sun and Moon listed alongside Mercury and Venus in any planet encyclopedia.
For most readings the Sun, Moon and rising sign carry the most weight, because they describe identity, emotion and outward style. After that it comes down to emphasis — the planet with the most aspects or an angular house position will usually be more prominent than its neighbours.