Hi there, can't remember rightly, but I think that a 12 hour night is the ideal, but an eight hour night is the norm for 1-3 month olds, ie: a longer period of time which may be interupted by feeds, but still the lo goes back to sleep and sees this as the night period. By the time they are reaching like 4-6 months old, the ideal would be bed at 7pm, and nighttime through to 7am, and then a 12 hour day where the naps are spread out and babe sees this as daytime.
I hope that made some sense x