Arachnid Nebula
The Arachnid Nebula was an interstellar gas cloud in the Alpha Quadrant. This cloud was located far from the planet . 

The Arachnid Nebula was featured on the front cover of "The Cosmos A to Z", an astronomy book by Laura Danly that claimed the nebula was six-point-five billion kilometers in diameter. The book was an inspiration to Jonathan Archer in his childhood.

In 2151, the starship  and a  vessel, the Vahklas, completed a survey of the nebula. The crew of the vessels found that it was actually more than eight billion kilometers in diameter, not six-point-five billion. They also noted over twenty million cubic meters of disodium and traces of ethylchlorate in the nebula. Enterprise intended to send back the new information to help revise the astronomy books. ()

In 2399, the location of the Arachnid Nebula was labeled in a star chart that was in Fleet Admiral Kirsten Clancy's office at Starfleet Headquarters. () 

de:Arachnoidea-Nebel
ja:アラクニド星雲
nl:Arachnidnevel
Nebulae