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The predominant autumn constellations are Perseus, a hero of Greek legend; Pegasus, Perseus' winged horse; the mythical princess Cassiopeia; queen Andromeda, her mother; and Aries, the ram.

Horn-shaped Andromeda is adjacent to the Great Square of Pegasus. Sirrah, one of Andromeda's brightest stars, also forms the northeast corner of the Great Square. A blue-white star, Sirrah is 1.5 times the Sun's diameter and lies 100 light-years from Earth.

Two other stars of equal brightness are located in Andromeda. They are Mirach and Almach. Almach is a triple star system located 260 light-years away. Two of its blue and yellow components can easily be seen through small telescopes.

The Andromeda Galaxy (M31) lies above the midpoint on a line from Sirrah to Almach. It is the most distant object visible to the unaided eye. Though no longer seen from Montreal, this vast stellar island appears as a faint, luminous spindle under very dark skies. Its spiral structure is slightly larger than the Milky Way and contains over 300 billion stars. Though the Andromeda Galaxy is 2.25 million light-years away, it is so vast that it stretches across the sky a distance equal to six full moons.

Aries, a small zodiac constellation, lies beneath Mirach. Its brightest star is Hamal, an orange giant 13 times the Sun's diameter that is situated 60 light-years away."