The asteroid 2008 QS11 has been discovered by the Siding Spring sky Survey (MPC code #E12) on 27 August 2008 at about magnitude 18.
The absolute magnitude of 19.8 suggests a diameter within a factor of two of 350 m (1). Due to its size and the proximity of its orbit to Earth's, this object has been classified as a "Potentially Hazardous Asteroid" by the Minor Planet Center. This object is also a target for the Goldstone Radar facility.
2008 QS11 (classified as an Apollo-type NEO) will reach on 02 October 2008 the minimum distance from Earth (0.02767 A.U.) with a maximum predicted brightness of about magnitude 14.
Here You can see the discovery mpec:
Below you can see our animation showing the motion of the asteroid in 30 minutes. At the moment of the shots 2008 QS11 was moving at 27"/min (magnitude 14):
UPDATE Radar image of 2008 QS11 from October 1: 0.125 usec (19 m) x 0.043 Hz
Range increases down and Doppler frequency increases to the right. The bandwidth is about 1 Hz and the visible extent is roughly 280 meters. Given that the radar can illuminate only about 1/2 of the object, its true size is thus about 560 meters.
By Ernesto Guido & Giovanni Sostero