On Saturday afternoon at 3 p.m. the moon will be at perigee, marking its closest pass to the Earth in 2011: a mere 221,565 miles away. Just 50 minutes earlier, the moon will have been officially full. It is a rare combination that happens only once every 20 years or so.
The last time we saw a moon this large was way back in March of 1993. If you miss it this year, you will have to wait until the year 2029 to see it again!