Cassiopeia

Cassiopeia is a constellation seen from Earth and named by humans after the Greek goddess Cassiopeia, who boasted about her beauty.

After the Krynoid on Earth was destroyed, the Doctor tried to take Sarah Jane Smith on a vacation to Cassiopeia. However, the TARDIS instead materialized in Antarctica as Doctor had forgotten to reset the coordinates. (DW: The Seeds of Doom)

A Charged Vacuum Emboitment that shunted entropy from N-Space into E-Space existed in this constellation. When the universe was hanging by a thread and entropy was taking over, the Doctor and the Master sent the reboot program from the Pharos Project on Earth to the CVE in Cassiopeia using a light speed overdrive. The signal arrived and restarted the CVE, stopping the entropy. (DW: Logopolis)

Many billions of years later, the CVE at Cassiopeia finally closed. (NA: Timewyrm: Apocalypse)