Multi-channel telescope can provide more than one wave band for remote sensing and then improve the efficiency of the
telescope. But it will increase the weight and bulk especially when correcting the aberrations with lenses which caused
by the oblique plane parallel plates splitters. It is a good method to correct the aberrations with free-form surface while
there is no lens to take up large space or to increase the weight. Free-form surface splitters were introduced in an F/3
off-axis TMA telescope with FOV 4.4°×0.2°, four channels such as visual, near wave infrared, short wave infrared and
middle wave infrared channels. The image quality is near the diffraction limit in each channel.