Cassini
discovered the division in 1675 using 90x magnification in a 2.5" refractor. Quite amazing considering the division is only around 0.5" arc. I find for me 200x-300x using my binoviewer, is the ideal for easily seeing the CD, and the pastel coloured bands on the planet itself. I really think that for most of us with normal/near normal eyesight 120x plus is needed to magnify the CD enough to clearly pull it out of the bright background of the rings. At the present "orientation" it should be an easy
target for a 6" to 8" reflector at 150x.(seeing allowing).