The Swedish science-satellite MATS (Mesopheric Airglow/Aerosol Tomography and Spectroscopy) willbe launched in 2018. This Masters project contributes to the verication of the optical design of MATSlimb-viewing instrument. The verication is performed in parallel and in collaboration with optical designwork carried out at Omnisys Instruments, a main industrial contractor for the MATS-project. Themajor objective is to verify the fullment of the scientic requirements and the imaging quality for theinstrument.The optical design was developed in the software OSLO by Omnisys Instruments and the vericationof the optical design is performed in the optical software Zemax. The results from Zemax simulationsconrm the results obtained by OSLO, with only minor dierences. A sensitivity study is performed onthe design to nd how the imaging quality is aected by various uncertainties in the instrument mechanicse.g. positioning of mirrors and CCDs. Such uncertainties can be induced during manufacture, launchetc. It is concluded that resulting requirements on accuracy of the instrument optics can be fullled withgood margin by available mechanical design and manufacturing techniques. Even in the most sensitivecases the mounting uncertainty is a factor 10 less than what is required by the image quality. Theimaging limitations give rise to various spot distributions when projecting an object on the CCD. Thisis important to take into account in the retrieval algorithm. To examine how these imaging issues andother limitations in the optics aect the tomographic retrieval results, the spot distributions are appliedto the retrieval using simulated measurement data. By insertion of optical aberrations into the forwardmodel which is a central part of the retrieval algorithm, it is observed that the sharpest forms may notbe visualized at the imaging limit.