Velocity Correction

An observed spectrum includes the motions of Earth and the Sun, which vary within $\pm$45 km s$^{-1}$ in V $_{\rm LSR}$ depending on the date of the observation. One can calculate the velocity resulted from these motions by the RVCORRECT task in IRAF. The velocity refferred to the local standard of rest can be obtained by adding the difference of the velocity between the observed velocity and the calculated V $_{\rm LSR}$ to that velocity.