The tradition of dimming the lights dates back to the earliest days of jump drive travel. It is considered a bad omen of the lights do not dim during jump drive engagement, leading to a misjump. Some passenger ships (or their parent companies) stage an elaborate ritual, inviting all passengers to a common room or rooms while a crew member describes what is occurring on the bridge with special attention paid to having the lights dim at the appropriate moment. Some will even go so far as to have backup lights or candles available in case all the power is needed for a successful jump, although that is just a show.
In the days before high output fusion power plants, many times the lights would dim as the jump drive was engaged, due to the high power required. Since then, the ritual of dimming the cabin lights at the moment of jump entry has become a tradition in an attempt to ward of misjumps. Many still believe that if a ship does not dim the lights during jump transition that it is a sign that they have misjumped.
During transit to the jump point, all systems are checked and made ready. At the time that the computer is engaged to execute the jump, the Captain of the ship will simultaneously manipulate a switch on their panel that will dim all passenger area lighting to approximately 60 percent normal for ten seconds or less. This is not an automatic or computer controlled. For the ritual to hold true, it must be physically initiated by the Captain at the moment of jump drive engagement.
Components and tools
A switch on the Captain's console.
While all on board a starship are participating, it is the Captain who must set the lights to dim at the proper moment.
During the engagement of the jump drive.