Eye of Harmony The Eye of Harmony , also known as Rassilon ' s Star , was a power source for the Time Lord s from which time travel was possible . Mechanics . The Eye was created by suspending time around an exploding star in the act of becoming a black hole , harnessing the potential energy of a collapse that would never occur . According to the Eleventh Doctor , you would " rip the star from its orbit , [ and ] suspend it in a permanent state of decay . " ( TV : " Journey to the Centre of the TARDIS " ) It poured forth raw artron energy which powered all TARDIS es and Time Scaphe s via a link created with morphologically unstable living organic matter . ( PROSE : " " ) This link existed as a beam and acted as a point of reference both temporally and physically for all TARDISes to calibrate from . A TARDIS could not receive energy from the beam outside of the normal continuum . ( PROSE : " State of Change " ) The Seventh Doctor once stated that the power to take control of a TARDIS in the Time Vortex , directing its flight and shutting down its systems , would have to be equal to the Eye of Harmony " at least . " ( PROSE : " Falls the Shadow " ) Legend . According to " The Book of the Old Time " , Rassilon , " with a great fleet " found the Eye of Harmony in a " black void " and returned it to Gallifrey at which " the people rejoiced " . ( TV : " The Deadly Assassin " ) Legends stated that the Eye of Harmony watched every Time Lord , wherever they went . ( PROSE : " The Adventuress of Henrietta Street " ) In the Panopticon . In the time of the Fourth Doctor , the Eye of Harmony lay secretly under the floor in the centre of the Panopticon . The Time Lords had forgotten its location , some believed it to be mythical or no longer in existence . The Eye was controlled by a crystal - shaped access system ( TV : " The Deadly Assassin " ) called the " Obelisk of Rassilon . " ( AUDIO : " Renaissance " ) The Rod and the Sash of Rassilon . The ancient artefacts ceremonially given to the Lord Presidents had a practical function to do with the Eye . The Rod of Rassilon opened the floor of the Panopticon like a key , allowing a black hexagonal obelisk to rise from the floor . This contained the Eye of Harmony . The Sash of Rassilon , also given to the President , supposedly served as means of protecting the wearer against the forces of a black hole . The practical functions of the Rod and the Sash and the true nature of the Eye of Harmony remained unknown to most on Gallifrey . ( TV : " The Deadly Assassin " ) Attempt to open the Eye . The Fourth Doctor deduce d the true use of the artefacts by interpreting enigmatic passages in " The Book of the Old Time " . He also realised that the name , the Eye of Harmony , symbolically described a black hole contained and balanced against the mass of the planet Gallifrey by Rassilon ' s engineering . had also separately come to the same conclusion . He deduce d that the Sash of Rassilon would give him immunity to the forces unleashed by the Eye if opened ( it didn ' t , due to being damaged by the time he used it ) . If it had opened , the Eye of Harmony would have functioned as a normal black hole and destroyed Gallifrey and also the Master , who had hoped it would trigger a new cycle of regeneration s for him . ( TV : " The Deadly Assassin " ) Dalek invasion . When the Dalek s unleashed the Apocalypse Element on the Seriphia Galaxy , the Sixth Doctor and Romana II attempted to use the power of the Eye to contain it , but it was insufficient . The Daleks on Gallifrey added their own mental energy to the Eye , which " did " contain the Element and created a new galaxy for them to transform into their new empire . During this incident the Doctor reprogrammed Gallifrey ' s security systems so that the Eye could only be opened by a human retina pattern . ( AUDIO : " The Apocalypse Element " ) Anti - Time . The Eye of Harmony was used to hold the Web of Time . The Neverpeople claimed a casket contained Rassilon ' s remains so it would be taken to Gallifrey , when really it contained Anti - Time . If it had infected the Eye of Harmony the Web of Time would have been destroyed . ( AUDIO : " Neverland " ) Fixing the Eye and the transduction barrier . After Romana , Narvin and Leela returned to Gallifrey from an alternative Gallifrey , and Lady Trey transplanted a future Capitol on the destroyed one , Romana had to balance the forces between the Eye and the transduction barrier . Romana had to perform extremely delicate calculations and if these weren ' t done correctly the imbalance could destroy Gallifrey . Due to extreme fatigue , and mistiming the barrier and eye became misaligned causing the death of Kolspen of Unvoss when he was leaving the planet . She went to the Eye to fix this mistake but due to the energies released by the unstable Eye , she started to regenerate . ( AUDIO : " Renaissance " ) However , this was later revealed to have been an artificial projection created by Lady Trey in the Matrix . ( AUDIO : " Ascension " ) During the Time War . During the Last Great Time War access to the Eye of Harmony ' s control system was restricted to the War Council . Heleyna used this to her advantage when she took an injured Ollistra to the Eye of Harmony chamber in Vassarian ' s Battle TARDIS and accessed it . She planned to destroy the Eye to stop the Time War as revenge for her grandfather ' s death in the first years of the war . In fact the Dalek Time Strategist used this to its advantage and planned to destroy the Eye to completely get rid of the Time Lords . The War Doctor managed to sever the TARDIS connection with the Eye and prevented its destruction . ( AUDIO : " Eye of Harmony " ) Inside the Doctor ' s TARDIS . All TARDISes built after a certain point , including the Type 40 the Doctor used , had a mathematically modelled duplicate of the Eye with all its attendant features . ( PROSE : " The Quantum Archangel " ) Narvin described all TARDISes as having a " fraction " of the Eye . ( AUDIO : " Forever " ) An aspect of the Eye appeared to have existed in the Doctor ' s TARDIS at least seven hundred years before the beginning of the Eighth Doctor ' s life . The Eighth Doctor claimed to that " [ i ] n seven hundred years , no - one has managed to open the Eye . " In this form , it was a stone structure shaped like a hemisphere which appeared to open outwards like an eyelid . While inside the Cloister Room of the TARDIS , the Master described the Eye as " the heart of this structure " . The Doctor said it was " [ t ] he power source of the heart of the TARDIS . " Both the Doctor and the Master claimed to Chang Lee that it belonged to the Doctor ; the Doctor referring to it as " my Eye " and the Master saying that " now it belongs to " him " " . The Eye responded to a physical linking device . The particular structure of a human eye had the effect of opening it . ( TV : " Doctor Who " ) If opened partially , the Eye gave visions of the past . ( PROSE : " The Eight Doctors " ) Opening the Eye allowed the Master and Lee to see a visual projection of the Doctor ' s past and present forms and let them see what the Doctor saw so that they could find him . It also assisted in returning the amnesia c Doctor ' s memories . The Doctor claimed that if he looked into the Eye , his " soul " would be destroyed , and the Master would be able to take over his body . Leaving the TARDIS ' Eye open for too long would result in space - time distortion , and any nearby planets would be " sucked through it " . ( TV : " Doctor Who " ) While in Caliburn House in 1974 , the Eleventh Doctor was able to utilise a " subset of the Eye of Harmony " to enter a pocket universe by running cables from the TARDIS . ( TV : " Hide " ) In an alternate timeline , the Eleventh Doctor , Clara Oswald , Tricky and Gregor Van Baalen once came across the Eye of Harmony when trapped inside the TARDIS . At that point , the Eye had the appearance of a star , one that was constantly on the verge of becoming a black hole . ( TV : " Journey to the Centre of the TARDIS " ) Dalek Eye of Harmony . After accumulating information from the Library on Kar - Charrat ( AUDIO : " The Genocide Machine " ) and their previous invasion of Gallifrey , ( AUDIO : " The Apocalypse Element " ) the Dalek Empire developed the use of harmonic energy derived from their own Eye of Harmony , based on that of the Time Lords . Several adjustments were made through the use of temporal barrier technology used on Kar - Charrat . ( AUDIO : " The Time of the Daleks " ) Alternative timelines . In an alternative timeline , Rassilon failed to finish the Eye of Harmony before his death and Gallifrey never achieved time travel . ( AUDIO : " Forever " ) In an another alternative timeline , Rassilon allied with the Cybermen and altered the Eye of Harmony to harvest regenerative energy from Time Lords that were trapped into a perpetual state of regeneration inside looms . The stored energy was intended to be used at the end of the universe to create a new one shaped by Rassilon . This timeline was negated by the Twelfth Doctor and Rassilon , who used the stored energy to restore the universe as if the Cybermen invasion never happened . ( COMIC : " Supremacy of the Cybermen " ) Behind the scenes . Neither the television story " The Invasion of Time " nor its novelisation , " Doctor Who and the Invasion of Time " , names the Eye of Harmony . However , according to the novelisation , the Sontaran Stor ' s attempted act of setting off a grenade in the Panopticon chamber when he couldn ' t conquer Gallifrey would destroy the planet due to there being " the power of a black hole " trapped directly beneath the Panopticon .