What a birth chart is, and what it is for
A birth chart (also called a natal chart) is a diagram of where the Sun, Moon and planets were at the moment of your birth, as seen from the place you were born. Astrologers use it as a symbolic description of temperament: what drives you, what you need, how you think, how you love and where your inner tensions sit. It does not forecast specific events, and it is not a diagnosis of anything.
Every chart is built from four ingredients, and it pays to be clear about them before reading anything:
Planets are the “what”. Each stands for a psychological function: the Sun for identity and purpose, the Moon for feelings and needs, Mercury for the mind, Venus for affection and taste, Mars for desire and drive, and so on. Astrology counts the Sun and Moon as planets even though astronomy does not. Each one is covered in planets in astrology.
Signs are the “how”: the twelve 30° segments of the ecliptic, the Sun’s apparent yearly path. A planet in a sign works in that sign’s style. Mars in Taurus wants and acts slowly and steadily; Mars in Gemini, quickly and in several directions at once.
Houses are the “where”: twelve sectors of the local sky, measured from the horizon and the meridian of your birthplace. Each house is an area of life — the 2nd money and possessions, the 7th partners, the 10th career. Signs depend on the date; houses depend on the time and the place. More in the astrology houses.
Aspects are the “with whom”: the angles planets form with each other. Two planets 90° apart (a square) pull against each other; 120° apart (a trine) they cooperate easily. Aspects turn a list of placements into a working system. They are explained in birth chart aspects.
What a birth chart is not: it is not your newspaper sun sign, which uses one placement out of ten; it is not a prediction of what will happen to you; and it is not scientific proof of anything. It is a symbolic language with two thousand years of tradition, sitting on top of entirely real astronomy. The astronomy — where everything was — can be checked to the arc second. The interpretation is a different kind of thing, and it helps to keep the two apart.
What you need: date, exact time and place
To calculate a birth chart you need three things: your date of birth, the exact time (clock time, ideally from a birth certificate or hospital record) and the place, which becomes a latitude, a longitude and a time zone. The date alone gives the slow planets and nearly always your sun sign. Without the time there are no houses and no rising sign, and the Moon can be uncertain.
The date fixes the planets. Most move so slowly that a day either way changes nothing: the Sun moves about a degree a day, Jupiter around five arc minutes, Pluto next to nothing. The exception is the Moon.
The time is the critical piece. The Earth turns 360° in 24 hours, so the ascendant — the zodiac degree coming up over the eastern horizon — advances on average one degree every four minutes. An hour’s error shifts it about 15°, half a sign; two hours will almost certainly change the sign. The midheaven and all twelve house cusps move with it, so an hour out can push a planet from the 9th house to the 10th and change the whole reading of your career. The Moon covers about 13° a day, roughly half a degree an hour: it takes about two and a half days to cross a sign, and if you were born on a changeover day, the time decides your Moon sign.
The place matters twice over. Longitude sets the true local time: each degree is 4 minutes, and two cities in the same time zone can be more than an hour of sun time apart. Latitude decides how the houses are shared out. In our own calculations, Placidus houses in Quito, on the equator, range from 27.6° to 32.6°; in New York, from 19.5° to 48.1°; in London, from 15.7° to 60.5°; in Reykjavík, from 6.8° to 114.9°. Above the Arctic Circle Placidus has no solution for some birth times at all.
If you do not know your birth time, the chart is still useful within limits: you can read the planets by sign and aspect, not the houses or the ascendant, and the Moon only if it stayed in one sign all day. If you know the time roughly, you can see how much the rising sign moves with it in the rising sign calculator, which also walks through the calculation by hand.
How a birth chart is calculated
A birth chart is calculated in six steps: convert the local clock time to Universal Time using the historical time zone, turn that into a Julian day, take the planets’ positions from an astronomical ephemeris, work out the local sidereal time, derive from it the ascendant, midheaven and house cusps, and finally measure the angles between planets to find the aspects. None of those steps is astrology. It is positional astronomy, the same as observatories use.
1. Local time to Universal Time (UTC). You apply the offset that was in force at that place on that date — not today’s — and take off daylight saving time if it was running. Historical time-zone databases (such as the IANA tz database built into every operating system) record thousands of changes. Britain ran Double Summer Time during the Second World War, two hours ahead of Greenwich. The United States left daylight saving to individual states and towns until 1966. This is where nearly all calculation errors come from.
2. Julian day. To do arithmetic with dates, astronomers count days continuously from noon on 1 January 4713 BC. That single number, the Julian day, sidesteps months, leap years and calendar reforms. A small correction called ΔT is added for the difference between atomic time and the Earth’s actual, slightly irregular rotation — about 47 seconds in 1976.
3. The planets’ positions. These come from an ephemeris: once a printed table, now a numerical model giving each body’s position at any instant. The reference ephemerides are NASA’s JPL Development Ephemerides (DE440 is the current one), and the Swiss Ephemeris packs that data for astrological software; it is what our engine uses. What is computed is the apparent geocentric position: seen from the centre of the Earth, corrected for light travel time, aberration and nutation. It is expressed as ecliptic longitude, 0° to 360°, measured from the vernal point — where the Sun stands at the March equinox. That point is 0° Aries in the tropical zodiac used in Western astrology: the signs are tied to the seasons, not to the constellations.
4. Local sidereal time. This measures which part of the sky is on your meridian. You start from Greenwich sidereal time, which runs 9.8565 seconds per hour faster than solar time, and add or subtract the longitude at 4 minutes of time per degree (subtract for west).
5. Ascendant, midheaven and houses. From local sidereal time, latitude and the tilt of the ecliptic (23.44°), spherical trigonometry gives two points: the ascendant, the ecliptic degree crossing the eastern horizon, and the midheaven (MC), the degree crossing the meridian overhead. Their opposites are the descendant and the IC. The twelve houses are laid out between them by a house system; the most widely used is Placidus, which trisects the time each degree takes to travel from horizon to meridian, and it is our default. The other systems, and how they differ, are in the astrology houses.
6. Aspects. Subtract the longitudes of each pair of planets and see whether the distance is close to 0°, 60°, 90°, 120°, 150° or 180°. “Close” is set by an orb, a margin of tolerance. Ours: conjunction 7°; opposition, trine and square 5°; sextile 4°; quincunx 3°. With those orbs an ordinary chart has 11.3 aspects on average, and eight charts in ten have between 8 and 15 (our own count over 20,000 random moments between 1930 and 2010).
A worked example: 11 May 1976, 3:20 pm, Mexico City
Take the same birth that is worked by hand on the rising sign page: 11 May 1976 at 15:20 in Mexico City (19°26′ N, 99°08′ W). Mexico was not on daylight saving time in May 1976, so the zone was UTC−6.
Step 1. 15:20 + 6 h = 21:20 UTC, same day. Step 2. That is Julian day 2,442,910.39. Step 3. The ephemeris puts the Sun in Taurus, around 21° into the sign. Step 4. Local sidereal time comes out at about 6h 02m, roughly 90.6° in degrees: the part of the sky culminating over the city was the June-solstice point. Step 5. At latitude 19.4° N, that gives an ascendant in the first minutes of Libra and a midheaven in the first degrees of Cancer.
There is a simple sanity check. At twenty past three in the afternoon the Sun had already crossed the meridian and was heading west, so in the chart it must sit in the western half of the sky, between the midheaven and the descendant. It does: the descendant falls at the start of Aries, the midheaven at the start of Cancer, and the Sun in Taurus lies between them. If a calculator ever puts an afternoon Sun below the eastern horizon, there is a time-zone error somewhere.
How to read the degrees and symbols
Every position in a chart is written as degrees and minutes within a sign, followed by the sign’s glyph: 21°17′ ♉ reads “21 degrees 17 minutes of Taurus”. Each sign has 30 degrees, numbered 0 to 29, and each degree 60 arc minutes. An “R” next to a planet means it was retrograde, and the number beside each placement in a table is the house it falls in.
Add the degrees of the signs before it and you get the absolute longitude: Taurus is the second sign and starts at 30°, so 21°17′ ♉ is 51°17′ from 0° Aries. That conversion is what makes aspects measurable: planets at 21° Taurus and 21° Leo are exactly 90° apart, a square.
One thing that trips people up: 21°17′ lies in the 22nd degree of the sign, just as 9:17 is in the tenth hour of the day. Some traditions (the “Sabian symbols”, for instance) round up for that reason. For ordinary reading, all you need to know is that 29° is the last degree of a sign and 0° the first.
The planet and point glyphs you will see on any chart:
| Planet or point | Glyph | Time per sign |
|---|---|---|
| Sun | ☉ | ≈ 1 month |
| Moon | ☽ | ≈ 2.5 days |
| Mercury | ☿ | 2–8 weeks |
| Venus | ♀ | 4–5 weeks |
| Mars | ♂ | 6–7 weeks |
| Jupiter | ♃ | ≈ 1 year |
| Saturn | ♄ | ≈ 2.5 years |
| Uranus | ♅ | ≈ 7 years |
| Neptune | ♆ | ≈ 14 years |
| Pluto | ♇ | 12–31 years |
| Chiron | ⚷ | 1.5–8 years |
| North Node | ☊ | ≈ 18 months |
| Ascendant / Midheaven | AC / MC | ≈ 2 h on average |
Aspects have glyphs too: ☌ conjunction, ☍ opposition, △ trine, □ square, ⚹ sextile and ⚻ quincunx. In an aspect table you will see something like “☉ □ ♂ 2°10′”: Sun square Mars with an orb of 2°10′, meaning the two are 90° apart give or take 2°10′. The smaller the orb, the stronger the aspect.
The twelve signs: glyph, element, modality and ruler
The twelve signs are grouped in two ways worth memorising, because every reading step uses them: four elements (fire, earth, air and water, three signs each) and three modalities (cardinal, fixed and mutable, four signs each). Each sign is a unique pairing of element and modality. The ruler is the planet that “governs” the sign; the modern ruler, where there is one, is in brackets.
| Sign | Glyph | Element | Modality | Ruler |
|---|---|---|---|---|
| Aries | ♈ | Fire | Cardinal | Mars |
| Taurus | ♉ | Earth | Fixed | Venus |
| Gemini | ♊ | Air | Mutable | Mercury |
| Cancer | ♋ | Water | Cardinal | Moon |
| Leo | ♌ | Fire | Fixed | Sun |
| Virgo | ♍ | Earth | Mutable | Mercury |
| Libra | ♎ | Air | Cardinal | Venus |
| Scorpio | ♏ | Water | Fixed | Mars (Pluto) |
| Sagittarius | ♐ | Fire | Mutable | Jupiter |
| Capricorn | ♑ | Earth | Cardinal | Saturn |
| Aquarius | ♒ | Air | Fixed | Saturn (Uranus) |
| Pisces | ♓ | Water | Mutable | Jupiter (Neptune) |
Cardinal signs open each season (Aries the northern spring, Cancer summer, Libra autumn, Capricorn winter), hence their link with initiative; fixed signs hold the middle of the season, hence persistence; mutable signs close it, hence adaptability. The full set of dignities — exaltation, detriment and fall — is in rulerships and dignities.
How to read a birth chart for beginners: the ten-step method
To read a birth chart, work from the general to the particular: start with the Sun, Moon and rising sign; then the balance of elements and modalities; then the chart ruler and where it sits; then the personal planets by sign and house, angular planets, the tightest aspects, aspect patterns, retrograde planets and the nodes; and finally put it all into a few sentences. That order prevents the most common beginner’s mistake, which is getting lost in one detail before you have the overall picture.
Keep the table from the calculator above open as you go. Each step leans on one of its columns: sign, degree, house, the R for retrograde, and the list of aspects with their orbs.
1. The big three: Sun, Moon and rising sign
Start with three placements; they are the skeleton of any reading. The Sun is your underlying identity — what you are heading towards and what gives you energy. The Moon is your emotional life: what you need to feel safe, how you react before you think, what settles you. The rising sign is the front door: how you approach anything new, the style you meet the world with, and what people notice first.
Read each by sign and, if you have a birth time, by house. Then compare them. A Capricorn Sun with a Leo Moon and Pisces rising describes someone with serious ambition, a real need to be appreciated, and a soft, hard-to-pin-down first impression: three layers that explain why people who barely know you tend to misread you. When all three share an element, the portrait is more uniform; when they clash, the friction is part of who you are.
The rising sign is the placement most sensitive to the birth time; you can read it sign by sign in the rising sign calculator.
2. The balance of elements and modalities
Count how many planets you have in each element and each modality. Use the ten planets plus the ascendant, and if you want more precision, give the Sun, Moon and ascendant extra weight (two points, say) and Uranus, Neptune and Pluto less (half a point), since your whole generation shares those.
You are looking for excesses and gaps. Lots of fire brings enthusiasm, drive and short patience; lots of earth, practicality and resistance to change; lots of air, ideas, talk and some distance from feelings; lots of water, sensitivity, emotional memory and a tendency to absorb the mood of a room. An empty element does not mean you “lack” it. It means that function does not come on automatically: someone with no earth often has to build practical habits on purpose, and frequently ends up doing it more deliberately than people born with plenty.
Modalities work the same way. Mostly cardinal means initiative (you start a lot); mostly fixed means staying power (you hold on, sometimes too long); mostly mutable means flexibility (you change plans easily, sometimes before finishing). This count gives you the overall temperament before you go into detail.
3. The chart ruler and where it sits
The chart ruler is the planet that rules your rising sign: Mars for Aries rising, Venus for Taurus or Libra rising, Mercury for Gemini or Virgo rising, and so on (see the signs table above). It is one of the most important planets in your chart, because the ascendant describes you and its ruler shows where that energy is headed.
Look at three things: its house (the area of life where your story plays out), its sign (in what style) and the aspects it receives. With Libra rising the ruler is Venus; if Venus is in the 10th house, much of your life points towards career and public standing, probably with a diplomatic or aesthetic flavour. If it were in the 4th, the pull would be towards home, family and private life.
For Scorpio, Aquarius and Pisces rising you can use the traditional ruler (Mars, Saturn, Jupiter) or the modern one (Pluto, Uranus, Neptune). A sensible approach is to read both and favour the traditional one, which is personal; the modern ruler sits in the same sign for millions of people.
4. The personal planets by sign and house
Next read Mercury, Venus and Mars, which with the Sun and Moon are the personal planets. They move fast, so they are what most separates you from someone born a few weeks earlier or later. For each, build a sentence from the formula function + style + area: the planet says what, the sign says how, the house says where.
For example: Mercury (the mind) in Virgo (precise, analytical) in the 6th house (daily work): you think best with a concrete problem in front of you and notice details everyone else skips. Venus (affection) in Aries (direct, impatient) in the 5th (romance, play): you fall fast, you like a challenge, and courtship feels like an adventure. Mars (action) in Cancer (indirect, protective) in the 2nd (resources): you spring into action mainly when your own material security, or your family’s, is on the line.
Then add Jupiter and Saturn, the social planets, which change sign roughly every year and every two and a half years. Jupiter shows where things come easily and you have confidence; Saturn, where you move slowly and carefully, with a fear that time turns into mastery. Each planet is described in full, with house examples, in planets in astrology.
5. The angles and angular planets
The four angles are the ascendant (AC, cusp of the 1st house), the IC (4th), the descendant (DC, 7th) and the midheaven (MC, 10th). A planet close to one of them — within roughly 5° to 8° — is called angular, and it shows far more than the rest: it acts outwardly, visibly.
A planet on the ascendant colours your physical presence and how you walk into a room (Saturn there gives gravity and reserve from childhood; Jupiter, an expansive presence). On the midheaven it shows in your career and reputation. On the descendant it turns up in the people you attract and how you pair up. On the IC, in your family of origin and private life.
Read the midheaven sign too: it speaks to vocation and public image even with no planet nearby. A historical footnote: in the 1950s and 60s the French statistician Michel Gauquelin published studies reporting that elite athletes were born with Mars just past rising or culmination more often than chance would predict. The result has been argued over ever since and is not considered established, but it is where the modern emphasis on angular planets comes from.
6. The tightest aspects first
Sort your aspects by orb, smallest first, and read the top three or four before anything else. An aspect with a 0°30′ orb is close to exact and felt all the time; one at 6° is at the edge and weighs little. Give extra priority to aspects involving the Sun, Moon, ascendant or chart ruler.
The type of aspect says how the two functions relate. A conjunction (0°) fuses them: you cannot use one without the other. An opposition (180°) sets them against each other and is often lived through other people. A square (90°) creates friction — inner conflict and, for exactly that reason, motion. A trine (120°) lets them cooperate without effort, sometimes so easily you never use it. A sextile (60°) is an opportunity that needs a small push. A quincunx (150°) links two things that do not understand each other and need constant adjustment.
Example: Moon square Saturn within 1° describes someone who learned early to contain feelings and not to ask; as an adult you often give others stability and find it hard to accept any. Read that before a 4° Venus–Jupiter trine, which is pleasant but less defining. Every combination is covered in birth chart aspects.
7. Aspect patterns: stellium, T-square, grand trine
Some aspects link up into shapes that dominate a chart. Look for them after reading the individual aspects, because they change the weight of everything before.
A stellium is a cluster of three or more planets (many astrologers want four) in one sign or house. That sign or house becomes the chart’s centre of gravity, even if your Sun is elsewhere: three planets in the 6th make daily work the main stage.
A T-square is two planets in opposition that both square a third, the focal planet. It is the pattern of productive tension: the focal planet takes the pressure of the opposition, and it is where you will work hardest and, usually, achieve most. The empty house opposite the focal planet is traditionally read as the release point.
A grand trine is three planets roughly 120° apart, usually in the three signs of one element. It gives a fluid talent in that element, along with a risk: comfort. Less common are the grand cross (four planets in two crossing oppositions) and the yod (two planets in sextile, both quincunx a third).
8. Retrograde planets
Note which planets carry an R. A retrograde planet appears to move backwards as seen from Earth; it is an effect of perspective, not a real reversal. In a birth chart it is read as a more inward, reconsidered function, one that matures late or works against the current.
Having some is entirely normal. In our own calculation from NASA’s DE440 ephemeris, Mercury is retrograde 19.2 % of the time, Jupiter 30.2 %, Saturn 36.4 % and Pluto 44.0 %. Two or three retrogrades are the norm, and the slow planets’ retrogrades barely register personally. The ones worth attention are Mercury, Venus (only 7.2 % of people) and Mars (9.5 %). The figures planet by planet are in retrograde planets, and the most searched one has its own page: Mercury retrograde.
9. The lunar nodes
The lunar nodes are the two points where the Moon’s orbit crosses the ecliptic. They are always opposite each other, and eclipses happen near them. They move backwards through the zodiac, completing the circle in about 18.6 years, roughly 18 months per sign. Our engine uses the mean node.
In modern reading, the South Node describes what you fall back on by habit, the familiar ground you retreat to; the North Node, the direction you grow in even when it is uncomfortable. With the North Node in the 7th house and the South in the 1st, for instance, the arc runs from self-sufficiency towards partnership. Read them late in the sequence, as orientation, and always by house axis, not just by sign: everyone born within the same year and a half shares the sign.
10. Putting it into sentences
The last step is to turn everything into a handful of sentences. Look for repeated themes: if the same message turns up by three different routes (a sign, a house, an aspect), it is central; if it appears once, it is a nuance. Write the main sentence first, then the tensions.
A sample synthesis, for a chart with the Sun in Taurus in the 8th, Moon in Aquarius, Libra rising with Venus in the 10th, a lot of earth, and a T-square focused on Mars in the 4th: “You look for stability and depth (Taurus Sun in the 8th), yet your emotional life needs room and a certain distance (Aquarius Moon). You come across as courteous and tasteful (Libra rising), and that energy is aimed at career and public standing (Venus, the chart ruler, in the 10th). Stamina and practical sense you have in abundance. The main tension is at home: family and private space are where pressure discharges (Mars in the 4th as the focal planet), and learning to fight without breaking things is your unfinished business.”
Notice that no sentence comes from a single placement: each combines two or three. That is what reading a chart well looks like. The full report on the home page does this work with you over 59 pages, every planet, house and aspect explained in plain English.
Common birth chart mistakes
The most common mistakes are five: using the wrong time zone, mixing up the tropical and sidereal zodiacs, reading one placement in isolation, taking generational aspects personally, and believing in aspects that cannot exist astronomically.
The wrong time zone. This ruins more rising signs than anything else. Knowing the country is not enough; you need the offset in force on that date and whether daylight saving applied. An hour out moves the ascendant about 15°, reshuffles the houses of nearly every planet and shifts the Moon half a degree. Always sanity-check: born at sunrise, the Sun sits by the ascendant; at noon, near the midheaven; at sunset, by the descendant; at midnight, near the IC.
Mixing tropical and sidereal. The tropical zodiac, used in Western astrology, starts at the March equinox. The sidereal zodiac, used in Vedic astrology, starts from a reference star. Because of the precession of the equinoxes — the Earth’s axis shifts about one degree every 72 years — the two are now about 24° apart. That is why headlines claiming “your sign has changed” or announcing a “13th sign”, Ophiuchus, confuse signs with constellations: the tropical zodiac was never tied to the stars.
Reading one placement in isolation. “I have Mars in Cancer, so I can’t stand up for myself” is a sentence torn out of context. That Mars might sit in the 10th house, conjunct the midheaven and trine Jupiter, and then it describes someone who fights very effectively for their people. Nothing in a chart is read alone.
Taking generational aspects personally. The single most common aspect is Neptune sextile Pluto, found in 51.3 % of charts, because it was in orb from 1947 to 1996 and again from 2018 to 2033. The same goes for Uranus conjunct Neptune (1990–1996) or Uranus conjunct Pluto (1964–1968). They describe the climate of an era, not you. They only gain personal weight when one of those planets touches an angle, the Sun or the Moon.
Believing impossible aspects. Seen from Earth, Mercury never gets more than 27.8° from the Sun, and Venus never more than 47.3° (our calculation, 1900–2100). So the Sun and Mercury can only be conjunct, and the Sun and Venus can never be sextile, square, trine or opposite. If a website interprets “Sun square Mercury” or “Venus opposite the Sun” in your birth chart, the chart is miscalculated or the text describes a chart that cannot exist.
Other kinds of chart: sidereal, draconic, progressed and solar return
Besides the tropical birth chart — the one Western astrology uses and this page calculates — there are other charts derived from the same moment or from later ones. These are the four people ask about most.
Sidereal or Vedic birth chart
A sidereal chart uses a zodiac tied to the fixed stars instead of the seasons. You get it by subtracting the ayanamsa — the gap built up by precession — from every tropical position; on the system most used in India (Lahiri) it is now about 24°. So nearly everyone moves back a sign: a Sun at 21° Taurus tropical lands in the last degrees of sidereal Aries. Vedic astrology (jyotish) also uses whole-sign houses, puts the Moon at the centre and divides the zodiac into 27 lunar mansions (nakshatras). It is not “more accurate” than the tropical zodiac; it measures from a different starting point.
Draconic chart
A draconic chart takes the position of the lunar North Node as 0° Aries and re-plots every planet from there: subtract the node’s longitude from each position. The relationships between planets — the aspects — stay the same; only the signs change. It is used as a symbolic layer of “underlying intention” and especially in relationship comparisons. It is a modern, minority technique, best explored once the birth chart itself is familiar.
Progressed chart
A progressed chart (secondary progressions) uses the rule “a day for a year”: the planets’ positions 30 days after your birth describe your thirtieth year. The progressed Sun moves about a degree a year and changes sign roughly every 30 years; the progressed Moon moves about 12° to 13° a year, so it spends about two and a half years in each sign and completes the circle in about 27 years. It is used to read the chapters of a life, not the underlying character.
Solar return
A solar return is the chart for the exact moment the Sun returns to the degree and minute it held at your birth, which happens every year around your birthday, sometimes a day before or after. It is cast for wherever you are that day and read as the weather of the year ahead: the house the Sun falls in and the return’s rising sign are the first things to look at.
Frequently asked questions
What is a birth chart?
A map of where the Sun, Moon and planets were at the exact time and place of your birth. Astrologers use it as a symbolic description of character, needs and inner tensions; it does not predict specific events.
How is a birth chart calculated?
The local birth time is converted to Universal Time using the historical time zone, planetary positions are taken from an astronomical ephemeris, and the ascendant, midheaven and houses are worked out from local sidereal time and latitude. Aspects come from measuring the angles between planets.
Can I get a birth chart without a birth time?
Yes, but only the planets by sign and aspect. Without a time there is no rising sign and no houses, and the Moon, which moves about 13° a day, may be uncertain if it changed sign that day.
What do the degrees in a birth chart mean?
They give the exact position inside a 30° sign: 21°17′ ♉ is 21 degrees 17 minutes of Taurus. They matter mainly for measuring aspects between planets and for deciding which house a planet falls in.
Where do I start reading my birth chart?
With the Sun, Moon and rising sign; then the element balance, the chart ruler and the personal planets by sign and house. Read aspects starting with the smallest orbs.
What does R mean in a birth chart?
That the planet was retrograde: seen from Earth it appeared to move backwards. It is very common; Mercury is retrograde 19.2 % of the time and Pluto 44 %.
Is a natal chart the same as a birth chart?
Yes. “Natal chart” is the more technical term and distinguishes it from other charts such as the solar return or the progressed chart.
Why is my sign different in Vedic astrology?
Vedic astrology uses the sidereal zodiac, tied to the stars, which precession has now put about 24° behind the tropical zodiac. Most people move back one sign.