Was messing with the timing on the GTO last night in the driveway & noticed sparks from the back of the alternator while revving the engine

. Don't know if it's always done it before but it was dark & you could really see it with the hood open sitting inside the car. It charges fine & all lights work & battery stays charged. Now I know
nothing about electrical stuff (among other things

) but seeing those sparks and my front carb about a foot away didn't seem like a good combination.
Should a normally functioning alternator produce visible sparks?
http://kurtspontiac.homestead.com/TimSimpson66GTO.html