system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Trek TNG] Data has the overnight watch, and I noticed they lower/raise the lights to simulate day/night watch. I understand simulating daylight for the Day watch personnel, but why simulate night for those working that shift? Isn’t it their daytime?

Most Federation species are Diurnal right? It’s very difficult to work an overnight.
gpt
As someone who has stood watch plenty of times during the back watch you want it dark because there are many other places on board that are darkened due to people sleeping. If you keep your own space bright but walk into a a dark space you have absolutely no night vision and it takes quite a bit of time to adjust.

I figure it would be similar in space, people moving around go between decks and don't want to struggle with night vision.