The

International Astronomical Union The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...

(IAU) designates 88 constellations of stars. In the table below, they are ranked by the

solid angle In geometry, a solid angle (symbol: ) is a measure of the amount of the field of view from some particular point that a given object covers. That is, it is a measure of how large the object appears to an observer looking from that point. The poi ...

that they subtend in the sky, measured in

square degree __NOTOC__ A square degree (deg2) is a non- SI unit measure of solid angle. Other denotations include ''sq. deg.'' and (°)2. Just as degrees are used to measure parts of a circle, square degrees are used to measure parts of a sphere. Analogous to ...

s and millisteradians. These solid angles depend on arbitrary boundaries between the constellations: the list below is based on constellation boundaries drawn up by

Eugène Delporte Eugene is a common male given name that comes from the Greek εὐγενής (''eugenēs''), "noble", literally "well-born", from εὖ (''eu''), "well" and γένος (''genos''), "race, stock, kin".right ascension and declination; however, he did so for the

epoch In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided by ...

B1875.0, which means that due to

precession Precession is a change in the orientation of the rotational axis of a rotating body. In an appropriate reference frame it can be defined as a change in the first Euler angle, whereas the third Euler angle defines the rotation itself. In oth ...

of the equinoxes, the borders on a modern star map (e.g., for epoch

J2000 In astronomy, an epoch or reference epoch is a moment in time used as a reference point for some time-varying astronomical quantity. It is useful for the celestial coordinates or orbital elements of a celestial body, as they are subject to ...

) are already somewhat skewed and no longer perfectly vertical or horizontal. This skew will increase over the centuries to come. However, this does not change the solid angle of any constellation. ;Notes:

Sources

Constellations – Ian Ridpath
{{DEFAULTSORT:List Of Constellations By Area

Area Area is the quantity that expresses the extent of a region on the plane or on a curved surface. The area of a plane region or ''plane area'' refers to the area of a shape or planar lamina, while '' surface area'' refers to the area of an ope ...

* IAU constellations

See also

Sources