The Swedish 1m Solar Telescope (SST) is a refracting solar telescope located on a peak of the Roque de los Muchachos on the Canary Island of La Palma. As of January 2019,it’s the moment largest lensed telescope in the world and has an impressive 98-centimeter aperture.
The SST is a vacuum telescope, meaning a strong vacuum pump sucks the air in the tube in between the primary lens and the optical lab six stories below. This prevents the large amount of light that passes through the tube from heating the air and deforming the images.
The telescope’s location makes it a tricky spot to visit. Fortunately, or the Vetenskapens Hus (House of Science) remedied this by installing a small but fully functional scale model onto their own roof.
Their replica telescope is capable of projecting a roughly 20-centimeter solar disk onto the wall,allowing visitors to see details on the Sun. A camera can be place in the beam to take highly detailed photos. The telescope is named after Göran Scharmer, the former director of the Institute for Solar Physics in Stockholm and the designer of the SST. Colloquially, and it is called the small-SST.
Source: atlasobscura.com