Nocturnal can open the previous evening as in the registration instructions I gave earlier:
"Nocturnal (noc.)
These are daylilies which open in the late afternoon or early evening and remain open all night and close the following day."
Larry's EMO link from the Daylily Dictionary says the same thing:
"Some nocturnal daylilies be mistaken for EMO's but their flowers actually open the evening before and are open all night."
EMO isn't a registration term whereas nocturnal is. It could open after 6pm and still be nocturnal. If it opened after midnight possibly not.
