Figure 4: Rotational Doppler shift of the SHG as a function of rotation frequency and direction of the β-BBO crystal. Alignment of the β-BBO crystal and calibration of rotational speed.

A nearby star is the fastest-rotating one that astronomers have seen so far, at a latitude of about 40 degrees. The rotation rate of the V889 Herculis is significantly different from that of the ...

Thidé says that weather radar could exploit the rotational Doppler effect to detect tornadoes before they reach the ground. Two years ago, he proposed a similar method to detect the rotation rate ...