The primary element is a single fused silica lens, making it the largest optical refracting telescope in use in the world.

The SST is a vacuum telescope, meaning that it is evacuated internally to avoid disruption of the image from air inside.

This is a particular problem with solar telescopes because of the heating from the large amounts of light collected being passed on to any air causing image degradation.

The TRI-Port Polarimetric Echelle-Littrow[14] (TRIPPEL) is a Littrow spectrograph using a 79 grooves/mm echelle grating with a blaze angle of 63.43 degrees.

It allows simultaneous observations at 3 different wavelengths, can in principle exploit the full spatial resolution of the SST, and has good polarimetric properties.