“Healthy Sleep Habits, Happy Child” says that babies starting at around 4 mos of age generally wake up between 6am-8am and go down for a morning nap about 2 hours after waking up and then take a second nap starting sometime between 12-2 and a third nap starting sometime between 3-5pm. He also says that around 4 mos of age babies should start going to bed earlier at night, like between 6-8pm. It seems like alot of people on here have said their babies go to sleep around 8:30pm.