A large aperture is critical to provide the follow-up capabilities of faint sources detected by LSST and other imaging surveys, and to ensure there is sufficient signal to noise for target selection for follow-up studies with the upcoming VLOTs.
MSE has the largest primary mirror of telescopes in its class (11.25m) and a very wide field of view (1.5 square degree). These characteristics are essential to enable surveys of the faintest science targets spread over very large areas of the sky.
The wide field corrector design incorporates an atmospheric dispersion corrector. A novel design of this system additionally allows the effect of differential atmospheric refraction to be reduced by a factor of ~2. This maintains the excellent delivered image quality at the focal surface that enables small fiber sizes.
The altitude-azimuth telescope structure points at the sky as commanded. A hexapod at the prime focus maintains optical system alignment and compensates for flexure of the telescope.
The CFHT rotating enclosure will be replaced with a Calotte enclosure that is only 10% larger than the current size, while the foundation and much of the remaining infrastructure intact.
Building renovations and structural upgrades will be internal so the outward appearance of MSE will appear very much unchanged from CFHT.