flying in and out of night/day, do you guys really pay exact attention to the moment when the sun finally slips behind the horizon (+30 minutes) to EXACTLY divide a sector's time between day & night?
It's measured at the surface so even if we were to keep an eye on the exact time the sun disappeared / reappeared, we'd be inaccurate.
Personally I make my best estimate but as I don't need to count the hours towards any licence issue, I don't imagine I will get picked up on it!