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?

Skylore

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).

Description

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.

Legend: In the constellation chart above...
• Star colors represent their spectral types (even for double stars).
• Bright star labels are yellow; significant other stars are labelled in magenta.
• The size of each star indicates its relative magnitude.
• Constellation names are light blue.
• Grid lines represent either 10 degree intervals of declination above or below the equator, or intervals of one hour (=15 degrees) of right ascension (measured along the equator).
• Messier object numbers are pink.
• Galaxies are ovals: blue if spiral, yellow if elliptical, light blue if irregular.
• Globular clusters are gold starbursts.
• Open clusters are dotted white circles.
• Planetary nebula are green diamonds.
• Bright nebula are magenta squares.
• Dark nebula are grey rectangles.
• Green x's are x-ray sources.
• Purple O's with a diagonal slash through them are quasars.

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?

Nebulae

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

• Stars of Our Neighborhood

©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.

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