The Amargosa observatory was a Federation space station that was in service in the late 24th century. The observatory was located in orbit of the Amargosa star and was used for scientific research of it.
In 2371, the USS Enterprise-D answered a distress call of the observatory, which had been raided by Romulans, who were searching for their trilithium, stolen by the Klingon outlaws Lursa and B'Etor. The trilithium was used by the only member of the observatory's staff who survived the attack, an El-Aurian named Dr. Tolian Soran, to build a trilithium weapon, which is capable of stopping all nuclear reactions in a star, thereby causing its collapse. Prior to the Romulan attack, the station had a complement of nineteen personnel.
After Soran launched his weapon towards Amargosa, the star collapsed and the resulting level-12 shock wave destroyed the observatory, along with everything else in that solar system. (Star Trek Generations)
Background information
The interior of the station featured jewel button control panels, intercoms and graphic displays identical to those seen on the original USS Enterprise. This suggests either that the station was more than one hundred years old at the time of its destruction, or its computer systems were that old.
The model of the observatory was reused for the wormhole relay station in DS9: "Destiny".