The big three: Sun, Moon and rising.

1. Three clocks

A birth chart is the sky at one moment, and three things in it mark that moment at three different speeds. The Sun goes round the zodiac once a year, so it takes about a month to cross each sign: the Sun sign is shared with everyone born in the same few weeks. The Moon goes round once a month and takes two to two and a half days to cross a sign: the Moon sign is shared with everyone born in the same two days. The Ascendant, the point of the zodiac rising in the east, goes round once a day and changes sign about every two hours: the rising sign is shared only with those born in the same two hours at a similar latitude.

Year, month and day. That is why the three together are so much more particular than any one of them. Among the 356 people in StarMap’s dataset with a recorded birth time there are 314 different combinations of the three, out of 1,728 possible; the most common, Leo Sun, Aries Moon and Pisces rising, appears 4 times. One of them shares the example’s three.

♊︎2. The Sun: who you are becoming

The Sun sign is the one people mean when they ask yours, and it is read as the centre of the chart: what fuels a person, what they are growing into, the part of them that is most steadily itself. It is the easiest of the three to know, because it needs only the date, and the least private: a Sun sign describes the life a person is building in daylight.

The Sun moves about a degree a day. In the example it stands at 12° Gemini 47', so it had been in Gemini for about 13 days and had about 17 to go. The dates printed for each sign are averages: the Sun changes sign on a slightly different day, and at a different hour, each year, which is why a chart is computed rather than looked up. In the dataset, 207 of the 5,838 people without a recorded time (4%) were born on a day the Sun changed sign, and their pages show both signs.

As the chart page reads the example’s Sun: “A Gemini Sun connects. Ideas, people and conversations are its element, and Rafael Nadal probably learns by talking things through. This placement is happiest with two projects and a question nobody has answered yet.”

Each sign has an element and a mode, listed with the signs on the Learn page; the famous people with each Sun are at Gemini Suns, and so on round the circle.

♉︎3. The Moon: what you feel and need

The Moon sign is read as the inner weather: how a person feels, what they need to feel safe, how they are restored and what they reach for without thinking. Where the Sun is the public life, the Moon is the private one, and astrologers often say it runs the days more than the Sun does. People who know someone well tend to recognise their Moon sign before their Sun.

The Moon moves about 13° a day, so it crosses a sign in two to two and a half days and changes sign during the birth date on about four days in ten. In the example the Moon entered Taurus at 17:45 local time, 35 minutes before the birth, so the chart shows it at 0° Taurus 17'; without the time, the page would have to show both Aries and Taurus. In the dataset the Moon changed sign on the birth date of 2,585 of the 5,838 people without a recorded time (44%), and the Moon sign calculator shows both signs, with the local time of the change, whenever that happens.

As the chart page reads the example’s Moon: “A Taurus Moon feels through the body and its surroundings. On this reading, good food, familiar places and slow evenings are what restore Rafael, and sudden change lands hard. Once they feel safe, they can be the steadiest person in the room.”

The Moon in each sign, with the famous people who share it: Moon in Taurus, and the other eleven from there.

♏︎4. The rising sign: how you come across

The rising sign, or Ascendant, is the sign that was coming up over the eastern horizon at the minute and place of birth. It is read as the surface of a person: manner, bearing, the first impression, the way they walk into a room, and the lens the rest of the chart is seen through. It is also the start of the first house, so it sets the whole frame of the houses: change the rising sign and every planet moves to a different part of life.

The Ascendant moves about a degree every four minutes, a whole sign in roughly two hours, which is why it needs the time as well as the date, and the place as well as the time: the same minute in two cities has two different horizons. In the example Scorpio was rising from 17:30 to 20:00; at 18:20 it had been rising for 50 minutes and had 1 hour and 40 minutes to go, and the Ascendant stood at 9° Scorpio 51'. Only 356 of the dataset’s 6,194 people have a recorded birth time, so only their pages show a rising sign; for the rest, the rising sign calculator lists the hours of the day each sign was rising at the birthplace, so a parent’s “about teatime” is often enough.

As the chart page reads the example’s rising sign: “Scorpio rising comes across as intense and self-contained. People tend to sense that there is more going on than Rafael is saying; this rising sign keeps more back than it shows.”

Each rising sign, with the famous people who share it: Scorpio rising.

5. Reading the three together

Read them in order, then as a chord. The Sun says what a person is for, the Moon what they need while they do it, the rising sign how it looks from outside. When the three agree, people read the person correctly at first meeting. When they differ, the gaps are the interesting part: the private self that surprises people who know only the public one, or the quiet manner on someone with a loud Sun.

The quickest way to hear the chord is through the elements. Fire acts, earth builds, air thinks, water feels. Three placements in one element describe a person with one clear way of meeting the world; three different elements, as in the example (air Sun, earth Moon, water rising), describe one with several registers who may feel different from the inside than they look. Then the modes: cardinal starts, fixed holds, mutable adapts. The example: mutable Sun, fixed Moon, fixed rising.

Some combinations are a story in themselves. The Sun and the rising sign fall in one sign for people born around sunrise, when the Sun is itself on the horizon: 37 of the 356 timed people in the dataset (one in ten), close to the one in twelve that chance gives. The Sun and the Moon share a sign for people born within a day or two of a new Moon: 25 of them. All three in one sign, a birth at sunrise near a new Moon: 3. And 132 of the 356 (37%) have, like the example, one placement in each of three elements.

Every StarMap chart ends with the famous people who share its Sun, Moon or rising sign, ranked by how much of the sky they share, so the three are also the quickest way into the celebrity charts.

6. Without a birth time

Two of the three survive. The Sun sign needs only the date, except on the day or so each month when the Sun changes sign, and then the chart shows both. The Moon sign is settled on about six days in ten; on the others the chart shows the two signs and the local time the Moon crossed, and anything a family remembers (morning or evening, before or after lunch) settles it. The rising sign does not survive: without a time there is no Ascendant and no houses, and the wheel starts at 0° Aries. StarMap never guesses one; it shows the hours of the day each sign was rising and leaves the choice to the person who knows the day.

Where to find the time: a birth certificate or hospital record in countries that record it, a baby book, a parent’s memory tested against the rising sign calculator’s table. A time rounded to the hour is usually enough for the Moon and often enough for the rising sign; StarMap says when either changed within an hour of the time given, since recorded times are often rounded.