Astral map

In their first incarnation, the Doctor owned an astral map which recorded the astronomical locations of various stars and planets.

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

Barbara Wright once found the Doctor dusting the astral map with a hankerchief in the TARDIS control room. (PROSE: A Long Night)

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)

After discovering a planet where there should not have been one, the First Doctor and Barbara Wright looked for it on the astral map and various paper star charts, but were unable to find any clues there. (AUDIO: The Dark 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 First Doctor once used the map when they landed on Ulysses 519 to determine that the date was 10 February, which happened to be his companion Steven Taylor's birthday. (AUDIO: Return of the Rocket Men)

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