You open your sign's horoscope on an ordinary morning, more out of habit than belief. Leo: “a day to shine, to take the stage, to be seen.” And you, who at a party would rather be on the balcony with one good conversation, read that with the feeling of having opened your neighbour's post.

The conclusion comes in one of two versions. Either astrology is nonsense, or you're a Leo with a factory defect. Both start from the same assumption, that the sun sign on its own should account for a whole person.

It doesn't, and it was never meant to. The sign in the horoscope is the Sun's position on the day you were born, and the Sun is one piece among ten planets and points, spread across twelve houses. Knowing someone by their sun sign is like knowing someone by their surname: it says something about the family and almost nothing about the person in front of you.

The full picture comes from the whole chart, calculated with date, time and city. And that's where the person from the balcony usually turns up at last, contradictions and all.

I start with the Sun because it matters, a great deal. It describes what lights you up: the kind of thing that, when you do it, makes you feel more like yourself. The identity you build over time, the will to express yourself, what you stand for when someone asks who you are.

Except the Sun is never alone in a sign. It falls in a house, which shows where that light wants to show itself, and it receives aspects from other planets, which show who it needs to negotiate with. The Leo on the balcony might have the Sun in house 12, and then their shine happens backstage: in work done alone, in creations no one sees being born, in generosity that needs no audience.

Or they might have the Sun square Saturn. In that case there's a wish to be seen, strong and real, alongside an inner voice that asks “who do you think you are?” every time they raise a hand. Many people live with this their whole lives and call it shyness.

That's why the Sun reads better as a direction. It shows what you're learning to be, and it's common for someone to recognise their own Sun only after thirty, once they've had time to go after it.

If the Sun is who you want to be, the Moon is who you are when you're tired, hungry or scared. It describes emotional needs, what soothes you, your automatic way of reacting. It's the part of the chart that arrives before thought does.

Two people argue, and each one needs a different thing to feel normal again. Someone with Moon in Gemini processes by talking: they need to tell it, repeat it, hear their own story out loud until it makes sense. Someone with Moon in Scorpio needs time alone to digest before they can say anything at all. Together, the two end up hurting each other without meaning to. One insists on talking it through and the other feels invaded.

The Moon also explains the gap between what you show and what you feel. Someone with Sun in Aries and Moon in Cancer walks into any argument sure of themselves and comes home needing to be held. No one at work would believe it, and their family has known it all along.

And it's usually the piece that explains the wrong horoscope best. Many people who don't recognise themselves in their own sign recognise themselves the moment they read their Moon's description. The difference between the three central pieces is explained in sign, Moon and Ascendant, and it's the first step out of the magazine text.

The Ascendant is the sign rising on the horizon at the exact time you were born, and it describes the first impression: the way you walk into a room, face something new, and start things. Carl Jung called it the persona, the face we show the world, and the Ascendant looks a lot like it, with the difference that no one chose it. It came with the time.

That's why it confuses people so much. Someone with Sun in Sagittarius and Ascendant in Virgo seems, at a first meeting, contained, attentive to detail, someone who asks before giving an opinion. Three hours later they're proposing a trip for next week. Both impressions are theirs, and whoever only saw the first one thinks they already know them.

The Ascendant also brings a piece few people know about: the chart ruler, the planet that rules the Ascendant's sign. The house it falls in shows where your life organises itself. Ascendant in Aries has Mars as its ruler; if Mars is in house 4, the drive everyone sees out in the world finds its main subject at home, for better and for worse.

All of this depends on your birth time. Without the time, the Ascendant and the houses are left out, and with them, half of what makes you different from everyone else born on the same day.

After the three central pieces come the ones that describe everyday life, and they're the ones that make people close to you say “that's so you.”

Mercury is the way you think and speak. Some people think in a straight line and get irritated by beating around the bush, some only grasp an idea after seeing three examples, some discover what they think halfway through their own sentence. Mercury in Capricorn writes the three-line email; in Pisces it writes the three-paragraph one and still feels it left out context.

Venus is taste: what you find beautiful, how you show affection, what you value in a friendship. Some people love by doing things for the other, some love by saying it. A couple where each one speaks a different one of these languages can spend years feeling unloved, with the love right there, just written in another language.

Mars is action and anger. It shows how you go after what you want and what you do when you're crossed. Mars in Libra avoids a fight until the last minute and then explodes over something small; Mars in Taurus is slow to move and, once it moves, nothing shifts it.

None of these pieces reads on its own. The sign gives the style, the house gives the subject, and the aspects say who that needs to talk to.

There's a way of looking at the chart from a distance, before going into each planet: counting how many points fall in each element and each modality. It's the person's accent. You don't yet know what they'll say, and you already know how it will sound.

A chart with lots of Fire tends to act first and think along the way. With lots of Earth, it wants to see the result in hand. With lots of Air, it needs to talk, compare, understand. With lots of Water, it feels before anything else and decides based on what it felt. The modalities tell you the rhythm: cardinal signs start, fixed signs sustain, mutable signs adapt.

What's most interesting is usually found in what's missing. An empty element becomes a question the person spends their life answering. Someone with nothing in Earth can end up obsessed with organisation precisely because it doesn't come naturally, and it's common to see this person with the neatest diary in the office.

The count has its traps, because part of it comes from your entire generation: the slow planets spend years in the same sign. If you want to see this in numbers, you'll find it all in elements and modalities, and the old reading of the same four elements in the four temperaments.

Here's what no horoscope can do. The planets talk to each other through angles, which astrology calls aspects, and many of these conversations are arguments.

Think of someone with Venus in conjunction with Uranus. They want real intimacy, and when it arrives, they feel a huge urge to open the window and leave. Or someone with the Moon in opposition to Saturn, who badly needs comfort and finds it enormously hard to ask for it, because they learned early on that asking was a bother. From the outside, these people seem inconsistent. From the inside, they seem tired.

What the chart does at that point is give the argument a name, and a name changes a lot. A contradiction with a name becomes two legitimate needs competing for the same space, and once you have a need, you can negotiate with it: give each one time and place, let the people who live with you know, stop punishing yourself for whichever part showed up.

What I see most in readings is relief. The person arrives convinced they're complicated and leaves knowing they have two parts that simply hadn't been introduced to each other yet. And the trines tell the other half of the story: they show talents that flow so easily you don't even notice you have them, and that's exactly why you've never used them on purpose.

A personality reading describes tendencies. It does not predict events, it does not tell you what will happen to you next year, and it doesn't know whether you'll change jobs or move to a different city. The chart describes someone's way of being, and what that person does with it is theirs to decide.

It doesn't box you in either. People change, mature, learn to work with the parts that were once difficult. Someone's chart at twenty and at fifty is the same; the person, thankfully, has changed. Any reading that treats a position as a sentence is reading it wrong.

It isn't an excuse. “I'm like this because I'm a Scorpio” is the laziest use astrology gets, and it tends to show up right when someone has hurt someone else. Understanding a pattern increases your responsibility for it.

And it doesn't replace psychotherapy. If what brought you here is suffering, anxiety that won't let up, sadness that won't lift, the right place is a mental health professional. The chart can walk alongside that care, never in its place.

Finally, no conclusion comes from a single position. One isolated aspect is a guess. A reliable picture appears when several different pieces point the same way.

Take a piece of paper and write down three words that describe you. Without overthinking it, the first ones that come to mind.

Then ask three people who know you from different parts of your life — someone from work, someone from your family and an old friend — to do the same about you. Just three words, by message, no explanation.

The lists almost always miss each other. The one from work describes one person, the one from family another, and yours a third. The temptation is to think someone got it wrong. Everyone is describing a real piece: the colleague's usually recalls your Ascendant, the family's usually recalls your Moon, and yours, with any luck, the Sun you're building.

Keep the four lists. Once you have your chart in hand, compare them. It's a very concrete way to see that the person from the horoscope who seemed like someone else was actually a part of you, read on its own.

And the questions that come up most on this subject, with the short answer: