What Is a Birth Chart

A birth chart — janma kundali in Sanskrit — is a map of the sky at the exact moment and place of your birth. It records where each planet was positioned relative to the horizon and the twelve signs of the zodiac. You can cast your own birth chart, or explore the current sky without entering any details.

The chart is not a photograph of the sky as you would see it from outside the atmosphere. It is a geocentric diagram: Earth sits at the center, and the planets are plotted around it in the order they appear from your specific location. Two people born at the same clock time but different cities will have different charts, because the horizon — and therefore the rising sign — changes with geography.

The Twelve Houses§

The chart is divided into twelve segments called bhavas (houses). They are counted from the eastern horizon, the point in the sky where the zodiac was rising at the moment of birth. This point becomes the first house cusp and the sign occupying it becomes the lagna, the ascendant. The lagna is the single most time-sensitive point in any chart.

The houses move continuously as the Earth rotates. The ascendant changes sign roughly every two hours. This is why birth time matters: a difference of a few minutes can shift the ascendant into a different sign, altering the structure of the entire chart.

The Planets§

Classical Vedic astrology works with seven planets — the sapta grahas:

Graha	Sanskrit	Represents
☉ Sun	Surya	Soul, authority, father
☽ Moon	Chandra	Mind, emotion, mother
♂ Mars	Mangala	Energy, courage, siblings
☿ Mercury	Budha	Intellect, speech, commerce
♃ Jupiter	Guru	Wisdom, expansion, children
♀ Venus	Shukra	Desire, beauty, relationships
♄ Saturn	Shani	Discipline, limitation, longevity

Rahu and Ketu — the lunar nodes — are also included in interpretation, though they are mathematical points rather than physical bodies.

Reading the Chart§

Every planet occupies a house and a sign. The house tells you where in life the planet operates; the sign tells you how it operates. A planet in the 7th house (relationships) in Scorpio operates differently than the same planet in the 7th house in Taurus — same arena, different quality.

Layered on top: the natural relationships between planets, the planetary rulerships of each sign and house, and the aspects (geometric angles) between planets. Vedic astrology uses a system of whole-sign aspects distinct from Western astrology — every planet fully aspects the sign directly opposite it (7th from itself), and certain planets have additional special aspects.

The chart is a snapshot. What changes is the sky now — the current positions of planets relative to your birth chart, tracked through dasha periods and transits. But the natal chart itself is fixed. It is the coordinate system everything else is measured against.