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A complete step-by-step walkthrough – from birth data to finished chart – using a worked example
A Kundali (Janam Patri / birth chart) is a map of the sky at the exact moment and place of your birth. It captures which zodiac signs and planets occupied which houses, forming a unique cosmic fingerprint. Every element – the rising sign (Lagna), the nine Grahas, the 12 Bhavas, the Dashas – flows from three simple inputs: date, time, and place of birth. This page walks through every step of how we turn those three inputs into a complete chart.
The foundational methodology for constructing a birth chart from astronomical data
We will follow one example birth through every step to show how abstract numbers become a living chart:
Every Kundali begins with exactly three pieces of information. Each determines a different aspect of the chart:
Date of Birth – determines where the Sun and planets are in the zodiac. The Sun moves ~1° per day, so even one day changes your chart.
Time of Birth – determines the Lagna (ascendant). The rising sign changes every ~2 hours, so accuracy to the minute matters.
Place of Birth – provides the geographic latitude and longitude. Latitude affects which sign rises, and longitude converts clock time to the exact local solar time.
Astronomical calculations require Universal Time (UT), not local clock time. We also need the Julian Day Number – a continuous day count used by astronomers since 4713 BCE.
For our example:
IST = UTC + 5:30
10:30 AM IST = 05:00 AM UT
Date: 15 Aug 1995, UT 05:00
JD = 2449945.708 // Julian Day Number
T = -0.0439 // centuries from J2000.0
Sidereal time measures the Earth's rotation relative to the stars (not the Sun). It tells us which part of the zodiac is directly overhead right now. The LST at your birth location and time is the key to finding your Lagna.
For our example:
GST (Greenwich Sidereal Time) at 0h UT = 21h 33m
Correction for 05:00 UT = +5h 01m // sidereal day is 3m 56s shorter
GST at 05:00 UT = 2h 34m
LST = GST + Longitude/15
LST = 2h 34m + 77.209°/15 = 2h 34m + 5h 09m
LST = 7h 43m // = 115.7°
The Lagna (ascendant) is the zodiac sign rising on the eastern horizon at the moment of birth. It becomes the 1st house and anchors the entire chart.
For our example:
Lagna° = atan2(sin(LST), cos(LST)·cos(ε) - tan(φ)·sin(ε))
where ε = 23.44° (obliquity), φ = 28.61° (Delhi latitude)
Tropical Lagna ≈ 207.5° // Scorpio in tropical
Ayanamsha (1995) ≈ 23.8°
Sidereal Lagna ≈ 183.7° = Tula (Libra) 3°42'
Tula (Libra) rising means Venus-ruled personality: diplomatic, artistic, relationship-oriented.
Our astronomical algorithms (Meeus) give tropical longitudes – positions relative to the spring equinox. But Vedic astrology uses sidereal longitudes – positions relative to the fixed stars. The difference is the Ayanamsha, currently ~24°.
Lahiri Ayanamsha ≈ 23.85° + 1.397° × T
For 1995 (T ≈ -0.044): Ayanamsha ≈ 23.79°
Sidereal position = Tropical position - 23.79°
This is why your "Western sign" and "Vedic sign" usually differ by about one sign.
Using the Julian Day, we calculate the sidereal longitude of each of the nine Grahas.
| Graha | Sidereal° | Rashi |
|---|---|---|
| Sun | 118.5° | Cancer (Karka) |
| Moon | 253.0° | Sagittarius (Dhanu) |
| Mars | 171.3° | Virgo (Kanya) |
| Mercury | 132.1° | Leo (Simha) |
| Jupiter | 216.8° | Scorpio (Vrishchika) |
| Venus | 124.4° | Leo (Simha) |
| Saturn | 312.6° | Aquarius (Kumbha) |
| Rahu | 183.7° | Libra (Tula) |
| Ketu | 3.7° | Aries (Mesha) |
In the Whole-Sign house system (standard Vedic), the Lagna's Rashi becomes the entire 1st house. The next Rashi becomes the 2nd house, and so on.
Formula:
House = (Planet_Rashi_Number - Lagna_Rashi_Number + 12) % 12 + 1
Example: Sun in Cancer (4), Lagna in Libra (7) → (4 - 7 + 12) % 12 + 1 = 10th house
15 Aug 1995 · 10:30 AM IST · New Delhi
The North Indian chart is a diamond grid where house positions are fixed – House 1 is always at the top.
Reading the chart:
- Top diamond (House 1) = Lagna → Tula (Libra) with Rahu
- Houses run counter-clockwise from the top
- Rashi names label each house; planets shown at center
- Sun in 10th (career) = strong public presence
- Moon in 3rd (communication) = expressive mind
Not all planet placements are equal. Each Graha has signs where it is strongest (Uccha/exalted), weakest (Neecha/debilitated), or comfortable (Swa Rashi/own sign).
Dignity Hierarchy:
Exalted (Uccha) > Own Sign (Swa) > Friendly (Mitra) > Neutral > Enemy (Shatru) > Debilitated (Neecha)
Every planet casts Drishti (aspect) on other houses. All planets have a 7th-house aspect (opposite). Mars additionally aspects the 4th and 8th; Jupiter the 5th and 9th; Saturn the 3rd and 10th.
In our example:
Jupiter in 2nd aspects 8th → protects longevity house
Saturn in 5th aspects 7th, 11th, 2nd → discipline in marriage, gains, speech
Sun in 10th aspects 4th → career impacts home life
The Vimshottari Dasha system divides life into planetary periods based on the Moon's Nakshatra at birth.
In our example:
Moon at 253.0° sidereal → Purva Ashadha Nakshatra
P. Ashadha lord = Venus → born in Venus Maha Dasha
Venus Maha Dasha = 20 years total
Moon progress through P. Ashadha:
P. Ashadha span: 253°20' to 266°40' (13°20')
Moon at 253.0° → near the start → ~19.6 years of Venus remain
After Venus: Sun (6y) → Moon (10y) → Mars (7y) → ...
Yogas are special planetary combinations that indicate specific life patterns. Doshas are afflictions. Our engine checks for 11 yogas and 3 doshas automatically.
In our example:
Mars in 12th from Lagna → Mangal Dosha is present
Mercury + Venus in Leo (11th) → Dhana Yoga (gains house)
Saturn in own sign Aquarius → strong 5th house (intelligence)
A Kundali reading weaves all these layers: the Lagna reveals personality, planet placements show life areas, dignity shows strength, aspects create connections, lordships link houses, Dashas provide timing, and Yogas/Doshas flag special patterns.
Deep dive into each house's significations
Planets, their natures, and rulerships
16 Shodasvarga charts – D9, D10, and beyond
The Vimshottari planetary period system
27 lunar mansions and their meanings
Current planet movements and predictions
Algorithms behind our calculations