The Astral V Annex was a historical museum, noted for its interest in ancient space-going vessels. In 2366, upon the discovery of the Promellian Cruiser Cleponji by the USS Enterprise-D, Captain Picard requested that the Annex be contacted so that the ship could be catalogued and scheduled for retrieval. Unfortunately, it would never reach the museum - the Enterprise was disabled by the same field of aceton assimilators which had doomed the Cleponji a millennium before, and after escaping just minutes before the crew would've succumbed to the radiation created by the assimilators, Picard ordered the ship, and the asteroid field around it, destroyed so that no other ship would fall prey to the trap. (TNG: "Booby Trap")
According to an early draft of the script, the Annex was part of the Smithsonian Institution. (Star Trek Encyclopedia)