mirrored ceilings

so the dealers at the casino i play at use a mirror to check for blackjacks. thing is, the cieling is very shiny and i can get a pretty good look at whats in the mirror. Trouble is, i dont know what to look for. The tens and face cards have a second marking on the top above the main marking, i believe for the sake of allowing the dealer to check for blackjacks on an ace up. but somehow the dealers can see if they have an ace, too, on a ten up. i examined it for a while, and i believed that when something big and black or red showed up, the dealer had a 10 down. but then a lot of times what i thought was a ten was actually a 7 or 4. i feel like this could be a great moneymaking opportunity if i knew what to look for and knew some sort of basic strategy based on whether the dealer had a ten in the hole or not (but only on 10s and aces up). Moneymaking tips or ideas?

You should hit until you have at least 20.

Obviously, if the dealer is showing an A and has ten in the hole, there isn't much you can do, since he has a blackjack.

My experience, however, has been that the dealer inserts the cards into the mirror device either lengthwise or widthwise depending on whether the upcard is a ten or an ace. The dealer would only be able to see whether or not the hole card made a blackjack or not. This is done to prevent the dealer from unknowingly making facial expressions that pass information to an astute player.

the dealer has an ace up with a ten in the hole...you can take insurance.

If an ace is up the dealer puts the cards in the reader in one direction. If a ten is up, the dealer puts the cards in the reader in the other direction.

that's what I said.