What is a birth chart?

A birth chart is a map of where the Sun, Moon, and planets sat in the sky at the exact moment and place you were born. Astrologers read it as a symbolic portrait of temperament and tendency.

Do I need my birth time for a birth chart?

Your Sun sign needs only your date. Your Moon sign is refined by your time of day, and the rising sign requires both an exact time and birth location.

The Centerpiece · The Instrument

Cast your sky.

A birth chart maps where the sky sat at your first moment. Enter your birth date and time, and the observatory places your Sun and Moon on a living zodiac wheel — computed from real astronomy, not guessed.

Your Details

Where were you born?

Take your sky home

Generate a high-resolution poster of your chart — the wheel, your Sun and Moon at their true positions, drawn in the observatory's hand. Print-quality PNG.

How this is computed. Your Sun sign is exact from your date. Your Moon sign is calculated from a simplified lunar model and is accurate to about a degree — a precise birth time sharpens it near a cusp. The rising sign and the other planets need an exact time and birth location; those arrive with the full ephemeris engine. Astrarium is a lens for reflection, never medical, financial, or legal advice.