As discussed in #1209 , even though there are default units, the FITS standard document recommends explicitly stating the units in the header. This PR does that.
The cubes made by WSclean are in frequency and have CUNIT3 = Hz in the header. When converting to velocity CARACal deletes CUNIT3. This PR changes that behaviour, and changes CUNIT3 from Hz to m/s when converting the axis. If the reverse conversion is requested, CUNIT3 changes from m/s to Hz.
As discussed in #1209 , even though there are default units, the FITS standard document recommends explicitly stating the units in the header. This PR does that.
The cubes made by WSclean are in frequency and have CUNIT3 = Hz in the header. When converting to velocity CARACal deletes CUNIT3. This PR changes that behaviour, and changes CUNIT3 from Hz to m/s when converting the axis. If the reverse conversion is requested, CUNIT3 changes from m/s to Hz.