''Is the SA200 a replacement for the SA100? Most definitely not! For a given length of spectrum the SA100 still marginally out performs the SA200 when used in the standard configuration between the telescope and camera. For most users the SA100 is expected to continue to be the model of choice, particularly for those using cameras with small sensors, giving optimum performance for example with the SA100 mounted on the camera nosepiece. In circumstances though where it is not practical to achieve the optimum spacing from the camera sensor required for the SA100, the SA200 gives an opportunity to improve performance.'' http://www.threehillsobservatory.co.uk/astro/spectroscopy_16.htm