Sorry, Can't get an easy drag and drop Google earth placemark to work so here is the lat/lon from GEarth:
Lat: 42 35 19.92N (degrees minutes seconds)
Lon: 71 18 27.93W ( " )
This is the actual location of the 5/11/79 show.
Strangest show. My first. It was oversold by at least double the number of people that it should have held. Someone threw a bottle at Brent. Very odd.