The Swedish 1-m 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 is the world’s largest existing optical refracting telescope, with an impressive 98-centimeter aperture. (A larger one was built for the 1900 Paris Exhibition, but it was dismantled at the end of the event.)

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, 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 put 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, it is called the small-SST.