I took a faulty scope mount for a rifle and bought a LED maglight. They had about the same curvature on the base of the mount as the outside of the flashlight. I carefully superglued it to the center of the light.
Took an extra scope ring that fits to the faulty scope base and attached the ring to the scope. The base secures the light to the scope and I can see a good 100 yards out and it turns night into day looking through the scope.