Deneb IV

Deneb IV was the inhabited fourth planet orbiting the primary Deneb. This was the homeworld of the Bandi, a telepathic humanoid species, and the Denebian slime devil. The planet's internal heat generated an abundance of geothermal energy. In 2364, Deneb IV was at the edge of "the great unexplored mass of the galaxy". ( okudagram)

History
During a mission to Deneb IV in the mid-23rd century, Gary Mitchell, with his friend James T. Kirk, was tested for his ability at telepathy. Mitchell had a marked ability to sense the telepathic communication used by the Bandi. In at least three cases, he was capable of carrying long telepathic communication with selected inhabitants, scoring 80% or higher on comprehension. On one night, in a telepathic communication with a female inhabitant, Mitchell suffered from after-effects that lasted for a while. Kirk later stated that he'd been worried about Mitchell ever since that night. As a pun, Mitchell referred to her as a. 

By 2364, the Bandi had seemingly constructed Farpoint Station, a base which they subsequently offered to Starfleet. Intrigued by the extremely short time in which it was built, Starfleet sent the USS Enterprise (NCC-1701-D) on its maiden voyage to the planet in order to investigate the base. It was subsequently discovered that the station was in fact a spaceborne entity, enslaved by the Bandi. Upon this discovery, the entity was released, and Starfleet and the Bandi began planning to reconstruct the station. 

Background information
This planet was originally intended to be called "Cygnus IV". It was even named that in Gene Roddenberry and D.C. Fontana's final draft script of.

Michael Okuda recalled how Deneb IV was originally depicted in "Encounter at Farpoint"; "The beautiful shot of Deneb IV was actually a matte painting done by Industrial Light & Magic, and that was done on film." Speaking shortly before the release of Star Trek: The Next Generation - The Next Level Blu-Ray sampler, Okuda also compared the remastered version of the planet with the original, saying, "The planet is pretty much dead on with what was done in the original shot." This referring to the planetary shot of Deneb IV.

The planet surface of Deneb IV, including Farpoint Station and Bandi city, was in actuality a maquette, built by maquette specialist Gregory Jein. It, combined with a background matte painting, was filmed at ILM by visual effects cameraman Robert Hill. 

Both and the  classified Deneb IV as a M-class planet.

The planet model for Deneb IV was later modified and used to represent in, , , and.

The Denebian slime devil was identified as a native species to this planet in the chart "Comparative Xenobiology", which was first seen in the episode.

Apocrypha
According to The Worlds of the Federation, Deneb IV was called "Kidta" by its natives.

According to Star Trek: Star Charts, there were two planets that shared the same name. Both were located in the Alpha Quadrant and classified as M-class. In 2378, both worlds were Federation members.

Deneb Kaitos IV, also known as Beta 16 Ceti IV, was – according to the book – the Deneb IV mentioned in. The planet had one moon. In the mid-22nd century, this planet was a destination on the trade routes. (pp. 41, 44, "United Federation of Planets I")

Alpha Cygni IV, also known as Deneb IV, was the planet seen in "Encounter at Farpoint". The planet was located 3,320 light years from the Sol system. As the homeworld of the humanoid Bandi, the planet was united under a single government, Bandi, which had its seat in Farpoint. In 2364, this world signed a treaty with Starfleet. Under the terms of this treaty, Starfleet would administer Farpoint Station. Between 2364 and 2378, this world was admitted to the Federation. In the census of 2370, there were counted an estimated 450 million Bandi living on the planet. Points of interest were Farpoint Station and Old City. (pp. 12-13, 34, 41, "United Federation of Planets I")