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Chart foundations

What is a birth chart? Planets, signs, houses, and aspects explained

A birth chart maps calculated sky positions for one time and place, then organizes astrological interpretation into planets, signs, houses, and aspects.Reviewed · 2026-08-24 · Educational astrology content
Direct answer

Within astrology, a birth chart is a map of the Sun, Moon, planets, angles, and house cusps for a specific date, clock time, and location. Planets describe functions, signs describe style, houses describe life areas, and aspects describe angular relationships between chart factors.

Key points

  • The chart must be calculated before it is interpreted.
  • A Sun sign is only one position in a complete chart.
  • Angles and houses require a usable birth time.
  • Different settings can produce legitimate house or aspect differences.

Method

  1. Confirm the date, local time, place, and historical time zone.
  2. Choose the zodiac, house system, and aspect policy.
  3. Read the chart from repeated themes rather than one isolated placement.

Limits and responsible use

  • Astrology is a symbolic framework, not a scientific diagnosis.
  • An unknown birth time makes house and angle claims unreliable.

Sources and references