Doppler tracking and dopset

In a spectral line experiment one has to set up the LO chain in such a way that the receivers are tuned to receive a specific frequency range encompassing the spectral lines of interest. If one knows the radial velocity of an object the program dopset can be used to calculate what the sky frequency will be on a specific date and how it varies as a function of time due to the motion of the Earth around the Sun and the rotation of the Earth around its axis.

Before explaining how to run dopset, let us briefly review the various definitions relevant to the Doppler shift. There are three essential ingredients involved in translating a source velocity into an observing frequency: the rest frequency, the velocity definition, and the velocity rest frame. In the following, the rest frequency will be denoted as $\nu_{0}$, and the corresponding wavelength as $\lambda_{0}$.