|Eridanus is a long narrow constellation winding like a river from Orion's kneecap to points farther south. It is probably named after Eridu, an ancient city in in old Babylonia. Over the ages various cultures have given it various names and backstories, almost all of them river-ish.
At the southern end of Eridanus the bright blue star Achernar marks the end of the river. The name means "End of the River." It's one of the brightest stars in the whole sky and it's also one of the hottest.
The Eridanus Supervoid is a large desolate area without much in the way of any points of interest. If you are crossing that area, take plenty of water, a sweater, and use the restroom before you leave. It's about a billion light years across, making it the second biggest known void in the observable universe. It is also the region where a "cold spot" in the cosmic microwave background has led some bold and possibly insane cosmologists to suggest it could be the site of a quantum entanglement between our universe and another universe. Tempering this claim is the fact that some astronomers will say anything to make an impression on the first date.
The star Epsilon Eridani has a planet with a real name. In 2015 the International Astronomy Union, the same mischievous amalgam of malcontents that devalued properties on Pluto, officially chose the name Ægir, which had been proposed by a class of 8th graders at Mountainside Middle School in Colbert, Washington. The kids also supplied an improved name for the star, Rán. The names refer to a husband and wife team in Norse mythology. Rán is the goddess of the sea and Ægir is the god of the ocean. Hmmm... sea, ocean, I thought those were two names for the same thing, like car and automobile. But then what do I know, I drive a Fjord.
IC 2118 in Eridanus is called the Witch Head Nebula. It's a worthy name. What we are seeing here is a supernova remnant, which is to say, star-kaboom leftovers. She has a lot of matted stardust in her hair, and freshly born t-tauri stars extruding from her nose. Her breath emits dangerous concentrations of carbon monoxide. She appears to be staring longingly at the Orion Nebula. Nothin' says lovin' like somethin' from the coven.
Spock's home planet Vulcan is reportedly orbiting around the star 40 Eridani A, or it will be at least until it gets destroyed thanks to some renegade Romulans. Cataclysmic events in your own time-line may vary. Vulcans periodically return home to mate, a ritual known as "Pon Farr" which it turns out is not as enjoyable as it sounds. Spock has to hook up with his childhood paramour or he will experience severe side-effects. Certain Vulcan organs will turn blue and I guess it's quite painful.
Carpe Noctem. Oh, and um, Love Long and Perspire.