A psychochronograph was a machine that amplified the natural abilities of a psychic. When in use, the psychochronograph opened a gate to a pocket universe.
It consisted of a Metebelis crystal and a subset of the Eye of Harmony connected to a TARDIS.
The psychochronograph seemed to exhaust its user. (TV: Hide)
The Eleventh Doctor built a psychochronograph in 1974 in order to amplify the natural abilities of Emma Grayling and thus open a gate to a pocket universe to find Hila Tacorien. (TV: Hide)