Kasterborous (Cas-TER-bor-os) was the constellation in which the planet Gallifrey was located. (TV: Pyramids of Mars) The Sixth Doctor mentioned that Kasterborous was made up of seventeen suns. (AUDIO: Trial of the Valeyard) When explaining where he was from, the Doctor sometimes mentioned that Gallifrey was located in Kasterborous, (TV: Attack of the Cybermen, Voyage of the Damned, The Day of the Doctor, AUDIO: An Earthly Child) and so did Clara Oswald while pretending to be the Doctor. (TV: Death in Heaven)
The Sixth Doctor said it was "just to the left of Karn." (AUDIO: Vortex Ice) The constellation was named by the Minyans. As no Time Lord was allowed to know Gallifrey's personal future, TARDISes were prevented from entering Kasterborous after a certain date. (PROSE: Goth Opera)
Kasterbourous was also the name of the astrologist who gave the largest contribution to the "New Astrology", occurring between the third millennium and the beginning of the fourth millennium. The Time Lords appointed one of their constellations with that name. (PROSE: Short Trips: Zodiac[which?])
The Doctor's parents owned a summer house in the Kasterborous of another universe. (PROSE: The Infinity Doctors)
The Racnoss Wars were waged by the Time Lords in response to a precognition forseeing Racnoss Webstars swarming throughout Kasterborous. (AUDIO: Empire of the Racnoss)
Behind the scenes
- The word "constellation" is used in reference to Kasterborous as a fixed location. However, the word "constellation" normally refers to an alignment of stars as seen from a subjective location. It seems that Robert Holmes intended it to mean "Kasterborous Sector" or "Kasterborous System" [source needed], but the term "the constellation of Kasterborous" has been used consistently throughout the show, including as recently as The Day of the Doctor.