Astral map

The Doctor owned in his first incarnation an astral map which recorded the astronomical locations of various stars and planets.

During Susan's time in the TARDIS, the Doctor hid his "secret diary" in the lower compartment of the astral map. Oblivious that Susan knew his hiding place until his eighth incarnation, the Doctor continued to house his diary here for some time. (AUDIO: The Shoreditch Intervention)

Upon arriving on Vortis, the Animus forced the Doctor to use the map to discover the plans of the invading Menoptera. (TV: The Web Planet)

The First Doctor used the map again when the Drahvins allowed him and Steven Taylor to go back to the TARDIS to find out how many days remained before the planet they were on exploded. The Doctor discovered it was not a fortnight as they had originally been told, but merely two days before it collapsed. (TV: Galaxy 4)

The Twelfth Doctor at the South Pole tried to distract the First Doctor with his astral map after his unfavourable remark to Bill about his future self needing her for cleaning the TARDIS. (TV: Twice Upon a Time)