we're visiting Ayutthuya in the next week or so and I'd like ot photograph the temples at sunrise or sunset, is this possible, or do they have opening times?   Hoping to catch them when they're as quiet as possible, before the hoards of tourists arrive by bus from BKK for the day

 

Any advice greatly appreciated 

looks like you can enter sites only at 8am (sunrise 6am): http://www.tourismthailand.org/Attraction/Wat-Phra-Mahathat--7

 

some lesser temples and ruins are free to enter if I remember right.

 

consider rent a scooter or bicycle evening before so you don't have to spend time with that in morning.