Arachna was a burned-out supernova located near the star Cepheus. The nearest starbase was Starbase 23.

In 2269, the USS Enterprise conducted a science survey to Arachna in order to acquire updated measures of radiation and volume of expansion as the nova entered its cycle of strongest emissions.

The Enterprise coordinated with Starbase 23 during this mission, which it contacted on stardate 55773.3 to inform them that they had arrived at the gas cloud and had started mapping. (TAS: "The Terratin Incident")