Understanding Your Vedic Natal Chart (Kundli)
A Vedic Natal Chart, known as a Janma Kundli, is a snapshot of the heavens at the precise moment of your birth. Unlike Western astrology which uses the Tropical zodiac, Vedic astrology (Jyotish) utilizes the Sidereal zodiac, which accounts for the precession of the equinoxes.
Key Components of the Calculation
- Lagna (The Ascendant): The zodiac sign rising on the eastern horizon at the time of birth. It represents your physical self, personality, and the lens through which you view the world.
- Ayanamsa: The mathematical difference between the Tropical and Sidereal zodiacs. This calculator uses the Lahiri Ayanamsa, the standard used by the Government of India for official Panchangs.
- Place of Birth: The Latitude and Longitude are critical because they determine the exact orientation of the horizon relative to the stars.
How to Use the Results
Once you calculate your Lagna, you can determine your primary planetary ruler. For example, if your Lagna is Aries (Mesha), your ruling planet is Mars (Mangal). In Vedic astrology, the Lagna is often considered more significant for daily life and health than the Sun sign.
Example Case:
If born on January 1, 1990, at 10:00 AM in New Delhi (Lat: 28.6, Long: 77.2, TZ: 5.5):
The calculated Lagna would be Aquarius (Kumbha). In Western astrology, this person might be a Capricorn Ascendant, demonstrating the ~24-degree shift between the two systems.
Frequently Asked Questions
Why is my Vedic sign different from my Western sign?
Vedic astrology uses the fixed positions of constellations (Sidereal), while Western astrology uses the seasonal position of the Sun (Tropical). The difference (Ayanamsa) is currently about 24 degrees.
What is the most accurate Ayanamsa?
While many exist (Raman, Krishnamurti, Fagan-Bradley), Lahiri is widely accepted by traditional Vedic scholars and professional astrologers as the most accurate for predictive purposes.
function calculateVedicChart() {
var bDate = document.getElementById('birthDate').value;
var bTime = document.getElementById('birthTime').value;
var lat = parseFloat(document.getElementById('latitude').value);
var lon = parseFloat(document.getElementById('longitude').value);
var tz = parseFloat(document.getElementById('timezone').value);
if (!bDate || !bTime || isNaN(lat) || isNaN(lon) || isNaN(tz)) {
alert("Please fill in all birth details correctly.");
return;
}
var dateParts = bDate.split('-');
var year = parseInt(dateParts[0]);
var month = parseInt(dateParts[1]);
var day = parseInt(dateParts[2]);
var timeParts = bTime.split(':');
var hour = parseInt(timeParts[0]);
var min = parseInt(timeParts[1]);
// 1. Calculate Julian Date (Simplified)
if (month <= 2) {
year -= 1;
month += 12;
}
var A = Math.floor(year / 100);
var B = 2 – A + Math.floor(A / 4);
var JD = Math.floor(365.25 * (year + 4716)) + Math.floor(30.6001 * (month + 1)) + day + B – 1524.5;
// Decimal Day/Time in UTC
var utcHour = hour + (min / 60) – tz;
var jdUtc = JD + (utcHour / 24);
// 2. Calculate GMST (Greenwich Mean Sidereal Time)
var T = (jdUtc – 2451545.0) / 36525;
var gmst = 280.46061837 + 360.98564736629 * (jdUtc – 2451545.0) + 0.000387933 * T * T – T * T * T / 38710000;
gmst = gmst % 360;
if (gmst < 0) gmst += 360;
// 3. Local Sidereal Time (LST)
var lst = gmst + lon;
lst = lst % 360;
if (lst < 0) lst += 360;
// 4. Calculate Lahiri Ayanamsa (Approximate: 23.85 in 1950, increases ~50.3" per year)
var baseYear = 1950;
var ayanamsa1950 = 23.15; // Rough start
var yearsDiff = (year + (month / 12)) – baseYear;
var currentAyanamsa = 23.15 + (yearsDiff * (50.27 / 3600));
// 5. Calculate Sidereal Ascendant (Simplified Tropical to Sidereal)
// Note: True Lagna requires complex Obliquity and Latitude correction
// This formula approximates the Rising degree for typical latitudes
var tanLat = Math.tan(lat * Math.PI / 180);
var sinEps = Math.sin(23.439 * Math.PI / 180);
var cosEps = Math.cos(23.439 * Math.PI / 180);
var alpha = lst * Math.PI / 180;
var lagnaTropical = Math.atan2(Math.cos(alpha), – (sinEps * tanLat + cosEps * Math.sin(alpha)));
lagnaTropical = (lagnaTropical * 180 / Math.PI) + 90;
var siderealLagna = (lagnaTropical – currentAyanamsa) % 360;
if (siderealLagna < 0) siderealLagna += 360;
// 6. Map to Signs
var signs = ["Aries (Mesha)", "Taurus (Vrishaba)", "Gemini (Mithuna)", "Cancer (Karka)", "Leo (Simha)", "Virgo (Kanya)", "Libra (Tula)", "Scorpio (Vrishchika)", "Sagittarius (Dhanu)", "Capricorn (Makara)", "Aquarius (Kumbha)", "Pisces (Meena)"];
var signIndex = Math.floor(siderealLagna / 30);
var degreeInSign = siderealLagna % 30;
// Display Results
document.getElementById('vedic-results').style.display = 'block';
document.getElementById('resLagna').innerText = signs[signIndex];
document.getElementById('resAyan').innerText = currentAyanamsa.toFixed(4) + "°";
document.getElementById('resSidereal').innerText = (lst / 15).toFixed(2) + " hours";
document.getElementById('resDegree').innerText = degreeInSign.toFixed(2) + "° in " + signs[signIndex].split(' ')[0];
// Scroll to results
document.getElementById('vedic-results').scrollIntoView({ behavior: 'smooth' });
}