Thoughts on duplicating masks for multi-line cubes

[djpisano3]

If you have a datacube that has multiple lines in it (such as for MUSE), it would be beneficial to be able to mask one line (such as H-alpha) and then copy that mask with a z-offset so that it overlaps with other emission lines in the cube (such as [SII], [OIII], etc.). This could be done by having the user duplicate the mask and adjust the offset with a slider, for example, or use the rest wavelength of known lines to apply masks.