€Classic observations by Nather (1978) and Patterson, Robinson & Nather (1978) found that DQ Her had a 72 sec oscillation that went away during eclipse
€Also found that the phase of the oscillation changed through the centre of the eclipse, as a result of first one side of the disk being eclipsed then the other
€Interpreted as resulting from the reprocessing of an X-ray beam sweeping the disk like a ³light house²
€Only recently seen in X-rays (scattered)