Pegasus

What is Pegasus?

Constellations· Autumn evenings (N) · the Great Square. The Great Square of autumn is the winged horse's body — and the corner star leads along Andromeda to the Andromeda Galaxy itself.

Where Pegasus is in your sky right now: https://nowsky.org/solar/sky?sel=con:Pegasus — location and time set automatically, no login.

Stars of the figure

The 3 brightest of the 8 stars used in the figure (8 lines). Lower magnitude means brighter.

Constellation basics

Figures are representative approximations. Source: compiled from NASA and IAU public data.

Frequently asked

When can I see Pegasus?

autumn.

What is the brightest star in Pegasus?

Enif, magnitude 2.4.

In one line, what is Pegasus?

Constellations — The Great Square of autumn is the winged horse's body — and the corner star leads along Andromeda to the Andromeda Galaxy itself.

Where is Pegasus in the sky right now?

Open the sky view for your location and time and it shows the position in the sky right now.

One corner of the square belongs to another constellation

The Great Square of autumn is drawn with four stars, but the one at the north-east corner, Alpheratz, belongs not to Pegasus but to Andromeda. Old charts shared the star between the two constellations and it also carried the name Delta Pegasi. When the International Astronomical Union fixed the constellation boundaries in 1930 it was assigned to Andromeda alone, so one of the four stars forming the horse's body officially lies in another constellation.

Before the boundaries were set, charts differed on which constellation a star between two figures belonged to. The 1930 decision divided the whole sky into 88 regions without gaps, and since then every star belongs to exactly one. The Great Square is a trace that rule left behind: as a figure, the four stars are simply joined, but as regions of sky, Alpheratz is the head of Andromeda.

The constellation in depth

Pegasus's body is the Great Square of autumn — a huge, conspicuous frame in the dim autumn sky, drawn as a winged horse flying upside down.

Counting naked-eye stars inside the Square is a classic sky-darkness test: zero from a city, dozens under truly dark skies.

From its corner, hop two stars along Andromeda to reach the Andromeda Galaxy. And in 1995 the first exoplanet around a Sun-like star — 51 Pegasi b, of Nobel fame — was found here.

The Great Square doubles as a sky-darkness meter: count the naked-eye stars inside it — zero or one downtown, a dozen or more under rural darkness. Follow the chain of stars from its corner through Andromeda and you arrive at the Andromeda Galaxy itself.

Related

Figures are representative approximations. Simulated positions use J2000 mean elements.