Complex sentence: The most common monochromator is the Czerny-Turner type whilst the most common polychromator is the Echelle type, even so the Czerny-Turner type can be (and is often) used to disperse the radiation onto CCD effectively making it a polychromator.
Split into simpler sentences: The most common monochromator is the Czerny-Turner type whilst the most common polychromator is the Echelle type. However, even the Czerny-Turner type can be (and is often) used to disperse the radiation onto a CCD effectively making it a polychromator.