A Stellium is the combination of three or more planets that occur together in a zodiac sign or a house. Possessing a Stellium in your birth chart is rare.
The astrological mandala, also called natal chart or astral chart is a record of the positioning of the stars at the time of birth. The mandala is a 360° circle and is divided into 12 parts and 12 signs, also called astrological houses. Each sign has 30°.