What Do You Need for an Accurate Birth Chart Reading?

• Birth date

  Fixes the Sun and the slow planets

  The date alone settles your Sun sign, and it settles Jupiter, Saturn and the lunar nodes too, because they move so slowly. It usually settles your Moon sign, unless the Moon changed sign that day.

• Birth time

  Fixes the rising sign and the houses

  The rising sign changes about every two hours and the houses turn with it. The Moon moves about half a degree an hour, so the time also decides its exact degree, your nakshatra pada and the start of your dasha periods.

• Birth place

  Fixes the clock and the horizon

  The place gives the time zone and the daylight saving in force on that date, which turn your local birth time into the one moment the sky is computed for, and the latitude and longitude the rising sign and houses depend on.

• Where you live now

  Fixes which day is today

  Your chart is fixed by where you were born, but your day is not. Horoskope asks where you live so that 'today' is your today, and so your morning email arrives at 8 AM where you are.

Because the sky turns. Every four minutes a new degree of the zodiac rises in the east, so the sign on the horizon changes about every two hours, and the twelve houses, the rooms of the chart where planets do their work, turn with it. Two people born on the same day in the same city a few hours apart can have different rising signs, different houses and a different nakshatra pada.

The bands are not equal, because signs rise at different speeds, and the difference grows the further a birthplace is from the equator. That is why a birth time that is off by an hour is enough to move a rising sign that sat near a boundary.

A birth certificate gives local clock time. To compute the sky, that has to become universal time, which needs the time zone and whether daylight saving was in force that day in that place. Both have changed over the decades in many countries, and it is exactly where hand-made charts go wrong: an hour of daylight saving missed moves the rising sign by about half a sign.

You can still have a useful chart. The date settles your Sun sign and the slow planets, and usually your Moon sign; what you lose is the rising sign, the houses and the exact Moon degree. Astrologers handle it in three ways:

1. 1

   A solar chart

   The houses are counted from your Sun's sign instead of the rising sign, the method newspaper columns use. Horoskope's Western readings do this when the birth time is missing.

2. 2

   A noon chart

   The planets are computed for midday, which keeps the Moon's error to at most half a day's travel, about six or seven degrees.

3. 3

   Rectification

   An astrologer works backwards from dated events in your life to estimate the birth time. It is skilled work, and still an estimate.

Whatever the method, a good reading says which parts are estimates. Horoskope's free reading does, and the dasha dates it gives for an unknown birth time are marked as estimates.

• ✓Your long-form birth certificate, or the birth register entry, which in many places records the time.
• ✓A baby book, a family horoscope (janam kundli) or a naming-ceremony record, which many Indian families keep.
• ✓Parents, grandparents or older relatives, noting how sure they are.
• ✓If the record gives a rounded time such as 10:00, treat it as approximate.

Your birth date, time and place are personal data, and together they can identify you, so share them only with a service whose privacy policy you have read. Horoskope's promise is short: we never sell your data, your chart never trains anyone's model, and you can export or delete everything, any time.