It’s unclear whether or not Hypnotic Pattern operates in the dead of night. As penned, it would be up in your DM to come to a decision. Individually, I'd personally rule that the Hypnotic Sample is made of light as it's an illusion and would, as a result, be noticeable https://cashmibsm.ltfblog.com/33306843/patron-hipnotico-an-overview