| PERSEUS Chart | Midnight Culmination | Skylore | Description | Special Stars |
| Nebulae | Star Clusters | Discussed in these Shows |

Constellation Data

  • Name: PERSEUS
  • Translation: Perseus
  • Abbreviation: Per
  • Genitive: Persei
  • Size: 24
  • Located Between: Andromeda, Capella (Auriga)
  • RA: 3 hours
  • Decl: +45 degrees
  • Season: Winter
  • Midnight Culmination: November 7
  • Pages where PERSEUS is discussed in Chet Raymo's 365 Starry Nights: 135,184,204-210

What is the Genitive form?
What is Right Ascension (RA)?
Is this constellation ever visible from my latitude? What is Declination?

Where should I look for a constellation on a date before or after its midnight culmination? What is Midnight Culmination?


Usually depicted carrying the detached head of the demon-woman Medusa, or Gorgon, who grew snakes for hair. Perseus married Andromeda after saving her from Cetus with the aid of Pegasus (see Andromeda).


Resembles a backward lambda. Located in the Milky Way, between Andromeda/Cassiopeia and Auriga/Taurus. Perseus contains no first-magnitude star, but a pair of beautiful binocular star clusters, known as the Double Cluster. Look for the Perseid meteor shower on August 12.

[star chart]

Star chart created with Voyager II Software for Macintosh, published by Carina Software. This is just a taste of what Voyager can do! For info on Voyager II software, call Carina Software at (510) 355-1266, write them at 12919 Alcosta Blvd Suite #7, San Ramon, CA 94583, or visit Carina Software's home page and check out Voyager II for yourself.

Special Stars

Mirphak (alpha-Persei). Magnitude: 1.8. Distance: 620 LY.

Algol (beta-Persei), the demon star, the Medusa's eye. Distance: 95 LY. Magnitude: 2.1 usually, fading every 2.9 days; in four hours it falls to magnitude 3.4; after 20 minutes it brightens. This exact regularity was discovered by G. Montanari in 1669. In 1782 the astronomer John Goodricke correctly suggested that Algol is a binary, with a faint companion that passes in front of Algol periodically making it wink. Following the changes of Algol makes for an interesting night with binoculars or even the unaided eye; check Sky and Telescope for the times of its dimming.

Table of 25 Brightest Stars.
What is apparent stellar magnitude?


M76, Little Bumbbell or Cork Nebula (Planetary nebula), mag. 11.4.

What are Nebulae?
Table of Messier Objects.
What is apparent Magnitude?

Star Clusters

M34 (Galactic cluster), mag. 5.8.

What are Star Clusters?

Discussed in these Shows

[Small Logo] ©1997 Welcome to the Basic Celestial Phenomena web site. To provide explanations of basic observational astronomy to students, teachers, families, and visitors to planetariums these pages have been written by an ex-OBU Planetarium Director, Kerry Magruder; the OBU Natural Sciences Coordinator, Mike Keas; and some of the students who work in the OBU planetarium.

The source for the logo is not a medieval woodcut!

These web pages may be printed, copied, and distributed for educational use by any non-profit educational group so long as they are not edited or altered in any way, nor distributed for profit, nor repackaged or incorporated into any other medium or product, and so long as full credit is given to Kerry Magruder.

If you find a link that does not work, please tell us which link does not work--and which page you are on. Contact us by Email with general inquiries or suggestions. Thank you.

Basic Celestial Phenomena
Constellations index
Basic Celestial Phenomena


Not a Medieval Woodcut

Planetarium pages

Theories of the Earth
History of Science


Page made with HyperNote Kerry Magruder, Home page or Email