I am a lark, up at 6.00, falling asleep by 10.00pm. DD had an unexpected rant at me recently about my failures as a mother when she was a teenager. When analysed it was clear that the real problem was that if I am a lark, she is an owl. Left to herself she wouldn'tgo to bed until 2.00pm and get up at mid day.
Therefore as she was hitting her peak activity rate between about 9.00pm and after midnight, I was hitting my zone down to sleeping level at 10.00.
Early morning: 6.00am to 8.00am, when I went to work and was at my brightest and best, she was deeply asleep.