Most 8-month-old babies still take two naps during the day. Depending on when the baby wakes up in the morning, the first nap can happen mid-morning. The second nap then happens mid-afternoon. You probably don't want the baby to sleep past 5pm so night sleep is not disrupted.
Your baby should still be taking regular naps, 2 or 3, every day. He should also be approaching the point where he'll be sleeping through the night. Encourage him to sleep in longer stints at night by reducing the naps he takes everyday. Create a solid schedule that he can rely on- bed time needs to be regular.
Children develop in different ways as do their sleep patterns. The average amount of sleep is 13 to 14 hours per day. Make bedtime a positive time and be consistent.
As babies get older they will start to take less naps. Your 8-month old should be taking about 2 naps a day, one in the morning and one in the afternoon. Then they should sleep a good 8-10 hours a night.