Pleiades Cluster
The Pleiades Cluster was a star cluster. The planet Velara III was located in this cluster. ()

An image appearing to be this cluster was contained in the Enterprise computer in 2254, when the Talosians scanned the recordings of the . ()

On stardate 41463.9, the  was mapping the cluster. During the mission, the Enterprise-D was asked by the Federation to visit terraformers on Velara III. Soon after resolving a conflict with microbrain, the lifeform native to Velara III, the Enterprise-D returned to an unnamed starbase with the surviving terraformers. ()

While on a date, on a holographic re-creation of Mars, with Danara Pel, The Doctor pointed out the Pleiades Cluster as among the many star formations and astronomical highlights seen from the surface of the planet. ()

Appendices

Background 
According to Star Trek: Star Charts ("United Federation of Planets II"), the Pleiades Cluster was located in the Alpha Quadrant.

An unused image of the Talos IV surface prepared for  showed the Pleiades very prominently in the Talossky, the brightest stars enlarged to the size of suns.  It would seem that the image from "The Cage" would suggest that Talos IV was located in this cluster.()

According to the Star Trek Encyclopedia (4th ed., vol. 2, p. 171), the Pleiades, also known as M45 or the Seven Sisters, was a region of space with young planets. It was a "cluster of about 400 stars in a 25-light-year , some 415 light years from Earth."

According to StarTrek.com, the Alcyones were from .  This is a real star that is part of the Pleiades cluster.

External links 
 
 

ja:プレアデス星団
de:Siebengestirn
Clusters