What happened to Luke's hand after his duel with Darth Vader?

I remember when I saw The Empire Strikes Back in the theater for the first time how shocked I was when Luke Skywalker lost his hand in that lightsaber duel.

"Whoa! Did I just see that?! Did Darth Vader really cut off Luke's hand?!"

Yeah, that was the real surprise in the movie. The part about Vader being Luke's father had already been spoiled for me.

But then I started to wonder: "What happened to his hand? Where did it go?" Well, the mystery has been solved...

(from JKA Gear)