Luna gave me cues as to her bedtime. She was here in my office and if I noticed she was going to her sleep branch and getting comfy I'd turn off the lights manually. If she continued with the same behavior I readjusted the lights (yes, I use timers
). Since I would often work late I would cover her cage once her lights were out and then took them (cover) off when I was done for the night so she could wake to the natural light coming in the window, and then her lights would come on. In the wild the sun doesn't suddenly turn on (lol!!) so mimicking nature is best. I did have her strip light go on first and then about 15 minutes later her basking light would come on. There were a few times where I messed up on the timers (we have frequent power outages and I would sometimes forget to reset!) and she would be in her dark cage, under her basking lights, body turned and flattened trying to take up the heat that wasn't there! Poor Lu-lu-be 
I do the same with Darwin (he is covered all night b/c he is in the bedroom and his lights wake ME up in the morning! I think it's nicer to do the gradual wake up. Gee, writing about Luna makes me sad 
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Chameleon Help & Resource Info
0.1 Veiled Chameleon - Luna. She's now hanging from her big jungle gym in the sky
1.0 Beardie - Darwin
0.2 felines - Kyndra and Lita
0.1 African Clawed Frog - Skipper
0.1 Mad. Hissers and she is on the loose!
0.1 Chilean Rose Hair Tarantula - Rosa Leigh
0.1 Goliath Bird-Eater Tarantula - Natasha
?.? Pinktoe Tarantula - no name yet