Does anyone know how to calculate Mercury's rotation rate? I mean, Doppler
data was taken in the 1960s to determine its period to be around 59 days.
This corresponds to an equatorial speed of only 3 m/s. I think a radio
telescope was used, with a wavelength of 12.5 cm. What is the corresponding
wavelength shift? I imagine very tiny! No calculations found online for
this, just the rotational period result. Wanted to make this a problem for
my HS astronomy students, but 3 m/s << speed of light in the Doppler
formula.