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£ 31 22 n stars and deep-sky objects

The charts show the major stars and deep-sky objects in each constellation. Individual stars are represented by dots that indicate their apparent magnitude (see scale at bottom of page).

Deep-sky objects

Distant, nebulous objects, such as clusters of stars, nebulae, and galaxies, are known as deep-sky objects. These are indicated on the constellation maps by the icons shown on the right. All are labeled with a catalog number, which may be a Messier number or an NGC or IC number (see p.147).

Open cluster

Globular cluster

Diffuse nebula

Planetary nebula or supernova remnant


Black hole

Star names

The brightest stars in a constellation are labeled with Greek letters, usually, but not always, in order of magnitude. The Greek alphabet is given below. Close pairs or groups of stars may share a Greek letter and are distinguished by superscripts. In Orion, a chain of six stars bears the letter Pi (p) with a distinguishing superscript—Pi1 (p1), Pi2 (p2), and so on. Other stars are known simply by a number—for example, 15 Orionis. The stars are numbered in increasing order of right ascension (from right to left on the charts). These are known as Flamsteed numbers because the stars concerned were cataloged by the first British Astronomer Royal, John Flamsteed (1646-1719).

linking lines join constellation figure degrees of declination deep-sky object

a Alpha

i iota

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