In astrology the planets are the actors in a birth chart. Each one stands for a part of you: how you think, what you want, how you love, where you push and where you hold back. The sign a planet sits in describes its style, and the house describes the area of life where it shows up. The planets themselves are real objects whose positions can be calculated to a fraction of a degree for any moment in history; what they mean is the interpretive tradition astrologers have built around them over two thousand years.
Astrologers call the Sun and Moon planets for convenience, though astronomers would call them a star and a satellite. Traditionally they are the luminaries, the two lights, and they are the heart of any reading.
The Sun represents your core identity and vitality: what you are here to become, what makes you feel most alive, the part of you that wants to be seen. It spends about a month in each sign, which is where the familiar "star sign" comes from. It rules Leo.
The Moon represents emotional needs, instinct, comfort and memory: what you reach for when you are tired or upset, and what makes you feel safe. It moves fast, about two and a half days per sign, so your Moon sign is often what separates you from other people with the same Sun sign. It rules Cancer.
Someone with the Sun in Leo and the Moon in Capricorn may present warmly and want to shine, yet only feel settled when things are under control and earned. Holding both at once is the work of that chart.
These three move quickly enough that their signs vary from person to person within a few weeks, which is why they describe everyday personality.
For relationships, Venus and Mars are read together; Venus and Mars covers that pairing in more depth.
Jupiter and Saturn move slowly enough that everyone born within a year or two shares their signs. They describe how a person relates to society, growth and responsibility, and their house positions and aspects often matter more than their signs.
Jupiter and Saturn were the outermost planets visible to ancient astronomers, and together they mark the boundary between the personal and the collective.
These three were discovered with telescopes (Uranus in 1781, Neptune in 1846, Pluto in 1930) and move so slowly that whole generations share their signs. They are often called generational planets. Their signs speak to the mood of an era; their houses and aspects to your personal chart make them individual.
Astronomers reclassified Pluto as a dwarf planet in 2006. Astrologers continued to use it, since its role in the chart comes from tradition and observation rather than its size.
The North Node and South Node are not planets but points. The Moon's orbit is tilted about five degrees against the Sun's apparent path (the ecliptic), and the nodes are the two places where those paths cross. Eclipses happen near them. The nodes always sit exactly opposite each other and move backward through the zodiac, completing a cycle in about 18.6 years, so they spend roughly a year and a half in each sign.
In Western astrology the South Node is often read as familiar habits and inherited strengths, and the North Node as the direction of growth that feels less natural but more rewarding. In Vedic astrology the nodes are Rahu (north) and Ketu (south), and they count as two of the nine grahas alongside the Sun, Moon, Mercury, Venus, Mars, Jupiter and Saturn. Traditional Jyotish does not use Uranus, Neptune or Pluto.
A useful rule: the faster a planet moves, the more personal its sign is. Your Moon sign is shared with far fewer people born near your birthday than your Saturn sign is, and your Pluto sign is shared with everyone born in a span of years. So when reading a chart, give the most weight to the Sun, Moon, Ascendant and the personal planets, and read the slower planets mainly through the house they occupy and the aspects they make to your faster ones.
Speed also shapes timing. Fast planets move through the sky in days or weeks and bring short moods; slow planets take months or years to cross a point in your chart, which is why they dominate the longer chapters of transits.
Every planet except the Sun and Moon periodically appears to move backward from Earth's point of view, a period called retrograde. A planet that was retrograde when you were born is traditionally read as turned inward: Mercury retrograde as thinking that works best when it can revisit and revise, Venus retrograde as values and affections that take time to settle. It is common, not a defect; many charts have at least one. Mercury retrograde explains the mechanics.
To see which sign and house each planet was in when you were born, you can see your own birth chart.
It is an old convention. The word planet comes from the Greek for wanderer, and ancient observers used it for the seven lights that moved against the fixed stars, including the Sun and Moon.
The Sun and Moon usually carry the most weight, along with the planet that rules your rising sign, often called the chart ruler. Any planet close to an angle or making many aspects will also stand out.
Yes, in modern Western astrology. Its reclassification as a dwarf planet in 2006 did not change how astrologers read it. Traditional and Vedic astrology do not use Pluto, Uranus or Neptune.
Nothing is missing. Most charts leave several signs empty. Those signs still appear on house cusps and are read through their ruling planets.