may direct a substantial portion of the seismic energy generated in a single lateral direction or within a limited range of angle with respect to the source longitudinal axis of the source in the example shown in fig1 a seismic receiver 50 may be disposed in another wellbore 18 a and may be conveyed therein using a second wireline 22 a one example of such a seismic receiver is described in u s pat no 4 715 469 issued to yasuda et al in such examples the seismic energy source if disposed in the wellbore 18 may be rotationally oriented using the rotator 10 so that its signal output is directed toward the other wellbore 18 a the instrument 14 flexible coupling 12 rotator 10 swivel 28 and cable head 26 are shown in more detail in fig2 in particular the rotator 10 may include a substantially cylindrical housing 10 b formed from a non magnetic material for example monel stainless steel titanium or an alloy sold under the trademark inconel which is a registered trademark of huntington alloys corporation huntington w va the housing 10 b may include through the wall thereof a plurality of longitudinally extending circumferentially spaced apart magnet pole shoes 10 a in other examples depending on the material from which the housing 10 b is made its thickness and the amount of torque needed to be generated by the rotator 10 to rotate the instrument the pole shoes 10.