Eri - Eridanus the River

Intro and Visual description

The River Eridanus flows northward (like the Nile) from the bright star Achernar (Arabic for "End of the River") to Kursa (beta-Eridani) near Rigel in Orion. Eridanus is the longest (not largest) constellation, spanning over 50 degrees of declination, and its many faint stars glitter like reflecting light off the surface of its waves.

Special Stars

Achernar, alpha-Eridani, is the 10th brightest star, but is not visible from most of the United States. No brighter star than Achernar is closer to the south celestial pole, which lies midway between Achernar and Crux the Southern Cross. Distance: 85 LY. Apparent magnitude: 0.5. Declination: -57 degrees south.

Kursa (beta-Eridani). Distance: 100 LY. Apparent magnitude: 2.8. Declination: -05 degrees south (near Rigel).

Epsilon Eridani is one of two nearby stars that resemble the Sun. Perhaps it also is surrounded by planets! (The other is Tau Ceti in Cetus the Whale.) Distance: 10.7 LY. Apparent magnitude: 3.7. Declination: -10 degrees south.

Origin and History

Eridanus is included in the ancient star catalogs of Eudoxos of Knidos, Aratos of Soli, and Ptolemy.

Skylore, Literature and Culture

The Nile to the Egyptians, the Po to Italians, and the Yellow River to the Chinese.

The ancient astronomer Hipparchos (ca. 150 B.C.) called Eridanus the "River of Orion."