NGC 457 — The Owl Cluster

NGC 457

Location in Sky

NGC 457 Location

Acquisition: AT115EDT. February, 2025


Quick Facts

  • Catalog: NGC 457.
  • Discovered: 1787, William Herschel.
  • Distance from Earth: 7,900 light-years.
  • Diameter: ~30 light-years.
  • Magnitude: 6.4.
  • Best Visible: Autumn.

    • Description

    NGC 457, widely known as the Owl Cluster or the ET Cluster, is a bright and easily recognizable open star cluster located in the constellation Cassiopeia. Its distinctive shape—featuring two bright “eyes” and a spread of fainter stars resembling outstretched wings—has made it one of the most iconic visual deep-sky objects for amateur observers.

    The cluster contains over 100 stars and is relatively young at around 20 million years old. Its two brightest members, Phi Cassiopeiae and HD 7902, form the “eyes” of the owl, with Phi Cassiopeiae being a luminous F-type supergiant thousands of times more luminous than the Sun.

    Because of its brightness and unique shape, NGC 457 is a favorite target for beginner and advanced observers alike and is visible even in small telescopes under dark skies.