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You need to decide which standard of rest you would like to use. The options are: None, Heliocentric, Geocentric, Topocentric or LSR. You also need to decide how you want this correction to be applied - to the center of each correlator board or to the four boards as a whole (thereby preserving the topocentric frequency offset between the boards). Typically, this choice depends on whether each board is centered on a known spectral line, or if you are doing a search in velocity space for an object. If you have centered each board onto a spectral line, then you likely want the boards to have their velocity corrections determined individually. If you are doing a search, in which case you want the relative spacings of your boards to remain the same, then you should have the velocity correction applied to the center of your boards. (In this case you would choose the spectral line for which you are searching. See Section 1.9 for more information.)
The last decision you need to make in this section is what velocity/redshift system you would like to use in your source list. Currently the options are: velocity(optical), velocity(radio), and z(optically determined redshift). A thorough discussion of these options can be found in Chris Salter's ``Notes Relevant to Spectral Line Calibration" which can be found at http://www.naic.edu/astro/misc.