If you blink really fast the heat generated by your eyelids makes a very bright light that is very similar to sun rays.

Fortunately for us the 4 astronauts were very well trained with this technique so they each took turns at lighting up the moon while the others took photographs.

In other news it was probably not a good idea to call it the dark side of the moon hence why it's refer to as the far side of the moon.

Good luck with the blinking, stay hydrated.