Constellation Data

Name: BOOTES Translation: Herdsman or Shepherd Abbreviation: Boo Genitive: Bootis Size: 13 RA: 15 hours Decl: +30 degrees Season: Spring Midnight Culmination: 2 May Pages where BOOTES is discussed in Chet Raymo's 365 Starry Nights: 79,93-100

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

One of the oldest constellations, mentioned in Homer's Odyssey.

Description

Skywatchers have long-repeated the catch-phrase "Arc to Arcturus" (Arc-TUR-us). Follow the curve of the Big Dipper's handle to the fourth brightest star in the sky. Arcturus belongs to the ancient constellation Bootes (BOW-oh-tees). Look for a pentagon above Arcturus forming the torso of the herdsman.

Some prefer to see Bootes as a one-scoop ice cream cone. Just to one side lies Corona Borealis, the Northern Crown. With bright Gemma ("Jemma") in its center, like a second scoop of ice cream that melted in the heat of summer and fell off the top.

In March of 1996 many North Americans observed the comet Hyakutake (YAH-koo-TAH-kee). When first visible, Hyakutake was near Arcturus, and from night to night it gradually passed between the Dippers before falling below our horizon at the end of April.

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.

Asterisms

Ice Cream Cone

What is an Asterism?

Special Stars

Arcturus means "guardian of the bear." It is an orange giant over 20 times brighter than the sun, the brightest in the northern hemisphere. Arcturus was the first star to be observed in the daytime, in 1635.

Arcturus moves across the sky against the background of the other stars. This "proper" motion was discovered by Edmond Halley in 1717, and shows that the so-called fixed stars are not completely fixed in their relative positions. You can't see Arcturus move on any given night, but it is slowly passing by the Sun, and is scheduled to disappear from our sky in just half a million years. ;-)

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

Discussed in these Shows

• Stars of Our Neighborhood
• Starstruck Tonight

©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!

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