Had the station originally been created as a checkpoint for wormhole traffic, it probably wouldn't have a "night" and a "day" at all, but rather a continuum of activity that was merely marked with the traditional Bajoran clock face for bookkeeping purposes. There would be no regular or discernible peak hours or quiet times for wormhole traffic, after all.
However, the station started out as a refining and intimidation outpost on Bajoran orbit. It did not appear to be on a surface-synchronous orbit - too low for that. Might have been daylight-synchronous, though, for whatever reason (a polar orbit that overflies the same location at the same time of surface day). There might be some hidden factor there to cause the Cardassians to organize the life aboard in terms of days and nights. Although I'd rather assume they would run their Bajoran workers ragged and not have any quiet shifts at all. Their station is threefold symmetric - if they needed maintenance downtime, they'd probably do it in 1/3 slices of the station and never have a stationwide night! "Night shifts" with dimmed lights and reduced activity and responsibilities would probably be a wussy Starfleet concept.
Yet the idea of a "night" for Quark's is obvious enough (he doesn't trust anybody else to keep it open when he gets his beauty sleep). Perhaps we are simply seeing the result of Quark's being the only business on the Promenade back during the Occupation when the schedules were set, as the Cardassians wouldn't exactly need to buy jumja sticks, nor would there probably be a Klingon restaurant aboard back then. Refining activities elsewhere on the station might proceed without interruptions, but the Promenade would still have its day and night - and the Cardassian masters would probably follow the same day cycle in their habitat section.
When the Feds took over, the Promenade became a broader business center, but of course everybody followed Quark's hours because sales would have been nonexistent when Quark's was closed!
Timo Saloniemi
