You may now want to rebin your object frame to constant wavelength steps 2-dimensionally with REBIN/MOS. For this you have to provide start, end, and step of the wavelength range you want to rebin with
Midas ...> SET/MOS rebstrt=start rebend=end rebstp=step
and then use
Midas ...> REBIN/MOS
The interpolation between pixels along the x-axis is taken from (LINEAR) and the order of interpolation along the y-axis between scanned rows is read from (1).