Telescopio Infrarosso del Gornergrat . The italian national telescope ( TIRGO ) is located on the northern tower of the Kulm Hotel at Gornergrat (3135 m altitude) near Zermatt . It is a 1.5m Cassegrain telescope with a wobbling secondary and optimized for infrared observations. ... with about 250.000 publicly available image . ... TIRGO general observer's guidelines . An introduction (in Italian) to infrared astronomy and TIRGO . Observing schedule . TIRGO Observer's home page . ...