The night time ceremony begins at 6:30pm and is an amazing time to visit.
I didnt go to the morning ceremony at 7am largely as I'm not an early bird but also because you cannot enter with shorts and shoulders must be covered. The days were very warm during our visit and we preferred to wait till the evening when the temperature was cooler.
This was a great choice. The sun is setting around this time and after you've been inside you can roam around the grounds in the dark with the other worshippers. It was very atmospheric and I wouldn't have wanted to miss it.