Pillar article
What a Birth Chart Actually Contains
A birth chart is three results from one moment: the sidereal sign of each graha, the houses counted from the lagna, and the Vimshottari period opened by the Moon's nakshatra. Drop the time and the houses disappear.
The inputs are not optional
The date places the grahas in signs. The time and the birth city place a sign on the eastern horizon. That sign is the lagna, the 1st house. The city is geocoded so the zone offset, in minutes, can be applied before the Julian day. Daylight saving changes the offset in regions that observe it, and the lagna can change with it. India uses Asia/Kolkata for every city, UTC plus 5 hours 30 minutes, with no daylight saving. A chart that asks only for a birthday has the Sun's sign and a guess at the Moon.
What you are allowed to ask each layer
Signs tell you dignity. The Sun exalts in Aries and debilitates in Libra. Mars exalts in Capricorn and debilitates in Cancer. Houses tell you the department. The 7th is marriage, the 10th is career, the 5th is children and learning. The dasha tells you the decade. Vimshottari assigns Ketu 7, Venus 20, Sun 6, Moon 10, Mars 7, Rahu 18, Jupiter 16, Saturn 19, and Mercury 17. Only the balance of the Moon's nakshatra lord is left at birth. A transit is weather inside that decade.
Jyothish SI's calculation, and its limit
The chart is sidereal, Lahiri ayanamsa, Swiss Ephemeris. A free account can generate the kundli and talk with the astrologer. Paid plans add PDF reports, more divisional charts, and WhatsApp transit alerts. None of that invents a result the ephemeris did not compute. The software will not ethically print a lifespan, a diagnosis, or a celebrity's planets from an unsourced time. The power of the chart is the three layers, read in order, from inputs you can defend.
Frequently asked questions
What if the birth time is unknown?
Signs and a Moon-based dasha can still be discussed only if the Moon's sign is secure. Houses need the lagna, which needs the time and city.
Which ayanamsa is used?
Lahiri, on a sidereal zodiac, with Swiss Ephemeris. The zone offset is applied before the Julian day.
Which layer times an event?
Vimshottari, the mahadasha and antardasha already running. A sign or a house without the period is a capacity, not a date.
Ask the AI astrologer about this topic
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D1, D9, D10, dashas, yogas, and transits, the same calculations referenced in this article.