Stars exist, normally, inside galaxies: huge stellar accumulations containing many thousand millions of members. The Sun itself belongs to one of such systems, normally called the Galaxy. For this reason, from the Solar System we contemplate a night-sky full of stars: we are seeing the closest companions of the Sun inside the Galaxy. But several astrophysical mechanisms are capable of ejecting stars from inside a galaxy directly into the intergalactic space. Those stars, the so-called hyper-velocity stars, reach speeds of hundreds of kilometres per second. Recently, the first hyper-velocity star from an external galaxy has been detected in a research leaded at the Ruhr-University (Bochum, Germany), and Calar Alto telescopes and instruments have played a key rule in this discovery…

Gamma-ray bursts (GRBs) are brief and intense flashes of gamma-ray radiation that occur randomly in any direction of the sky. After some decades of study, these very violent phenomena still give astronomers reasons for surprise. A new type of GRB-related explosion has been discovered recently, and Calar Alto telescopes have played their role in this story…

After passing the commissioning phase, the latest newcomer among the spread of instruments of Calar Alto Observatory is already at work: the high-resolution spectrograph known as CAFÉ. This device, designed and built at Calar Alto for its 2.2 m reflecting telescope, analyses in detail the light coming from celestial bodies in order to extract from it a rich wealth of astrophysical information of many kinds. CAFÉ will be one of the battle horses of the 2.2 m Calar Alto telescope from now on…