Frequency of being dealt an Ace in an Omaha session

[Alchemist]

I'm trying to determine the standard deviation of being dealt X hands containing at least one Ace in a session.

The probability of being dealt at least one Ace in O8 is:
1 - [(48/52)*(47/51)*(46/50)*(45/49)] = .2813

My last session of O8 I played 209 hands and 66 of those hands had at least one Ace.
My expected number of hands w/an Ace is .2813 * 209 = 58.8

But now I'm stuck trying to determine the SD. I must be overlooking something fundamental.