On the evening of Saturday, September 3rd, the dark edge of the Moon will cover the 2.3-magnitude star Delta Scorpii from the eastern and southern U.S. to northern Venezuela. The northern graze line runs roughly from New York City through central Texas to Baja California.
The timing is extremely convenient — anywhere from roughly 7 p.m. PDT to 10:30 p.m. EDT. It takes place in twilight in Baja and in fully dark skies everywhere else. However, the event will occur very low in the sky for people on the U.S. East Coast.
This is the brightest star occulted in 2011, and it's probably the year's best occultation for people in its visiblity zone. The Moon will be only 43% illuminated, so the disappearance should be visible without optical aid. But binoculars or a telescope will give a much better view.
See International Occultation Timing Association webpage for the precise circumstances at specific locations. See our Occultations section for articles detailing the how and why of occultation observing.