In 2001 I had the opportunity to observe at the professional spanish 1,5m-Ritchey-Chretien, a Teleskope of the Observatorio Astronómico Nacional (OAN) at Calar Alto. For this observing run I was on site together with some members of the Starkenburg-Sternwarte, see pictures.
Within the framework of the „Space Situational Awareness Programme“ of the European Space Agency (ESA) I have the possibility to use since December 2016 remote controlled the Schmidt – Telescope (formerly known as Großer-Hamburger-Schmidt) at Calar Alto, the German-Spanish Astronomical Center operated jointly by the Max-Planck-Institut für Astronomie (MPIA) in Heidelberg and the Instituto de Astrofísica de Andalucía (IAA-CSIC) in Granada. The released MPECs can be found here.
Weather at Calar Alto: