So just what the heck is egg candling? Here's a picture to give you a better idea.
I'm holding a flashlight up to the egg. If there are red veins present, which there are, that means it is fertile. The black "x" that I've marked on the eggs signifies "this side up". Reptile eggs are not like bird eggs...where the parents turn the eggs to keep the embryo from sticking. You don't want to rotate snake eggs, it could kill the developing baby inside.