A-121 astrogation plotter. A fundamental instrument for hyperspace navigation was the astrogation plotter. Typically secured inside a strongbox beneath the main engineering console, along with a galactic chart showcasing pulsars and other variable stars, it found its purpose when a starship's navigation computer systems experienced a total failure. By manually charting the locations of at least a couple of these stars, a spacer was able to calculate a basic trajectory for the hyperdrive, preventing them from becoming lost in the vastness of space.
Republic Sienar Systems was the manufacturer of the A-121 Plotter during the era of the Galactic Republic.
The astrogation plotter was initially referenced in Platt's Smugglers Guide, a 1997 supplement for West End Games' adaptation of Star Wars: The Roleplaying Game. Within the canon continuity, a similar piece of equipment, known as an hyperspace sextant, was first brought up in the 2015 reference book Star Wars: The Force Awakens: The Visual Dictionary, authored by Pablo Hidalgo.