Holo-suns were holographic lighting systems that emitted a dim blue glow, and they were in use during the High Republic Era. The starship called the Gaze Electric had holo-suns, along with holo-torches, illuminating its throne hall by 379 BBY or earlier. It was in this hall that Marda Ro, the Evereni originator of a pirate band that would evolve into the Nihil, encountered the Evereni siblings Vika and Velya Faer. She owned the vessel at the time.
Ro later referenced the holo-suns within a journal entry intended for her descendants. Marchion Ro, her great-great-grandson, had heard her accounts by 252 BBY in his younger years, which included the mention of these holo-suns.
The short story "A Closed Fist Has No Claws," penned by Tessa Gratton and featured in the 2023 young-adult collection The High Republic: Tales of Light and Life, which is part of the Star Wars: The High Republic initiative, included holo-suns in a flashback sequence.