Astronomy · Institutional reference
The constellations
International Astronomical Union
The IAU explains modern constellations as bounded areas of sky, distinguished from star-pattern drawings. This gives a precise astronomical comparison for the twelve astrological signs.
Open the source text ↗Where to begin
Read the definition of a constellation and the explanation of boundaries. A familiar figure between stars and an official area of sky are different things.
Keep in mind
The modern IAU convention is not a universal account of cultural star traditions. Do not substitute its constellation boundaries for equal 30-degree tropical zodiac signs.