Does the large 6-pointed star on a sectional warn of dangerous radar facility?
There are two stars:


The large multi-pointed Star (6 pointed in this case) is described in the Aeronautical Chart User’s Guide as an indicator of High Energy Radiation Areas. The Precision Acquisition Vehicle Entry Phased Array Warning System (radar) may be intense enough to damage avionics. Or, at least cause them to give false readings.   
The blue star with the clear circle in its center indicates that the airfield has a rotating light beacon and the beacon’s location relative to the field. The beacon’s location can be used to differentiate one airfield from another while in flight at night.


Reference: Aeronautical Chart User’s Guide