I think she has a senegals, so I'm not sure on there temps but would think 60s over night should still be safe.
as others have said if you do need heat over night (and can't heat the whole room) you should use a cermic heat bulb or some other source that doesn't put out ANY light.
I know my guys will go to sleep, and some times sleep through low light (such as me turning a light on in a ajoining room with the door open) but often they will wake up or at lest rouse, so I think anything more than what a bright moon lit night would be is to much.
if they are not getting a restful nights sleep it will affect thier health (just like it does ours). so figue out some way to safely heat with out light (if you do use a cermic heater make sure there is no cloth, papper, wood ect. near it.)