The horizontal-branch (HB) morphology of globular clusters (GCs) is mainly determined by metallicity. However, the fact that GCs with almost the same metallicity exhibit different HB morphologies demonstrates that at least one more parameter is needed to explain the HB morphology. It has been suggested that one of these should be a global parameter

Context. To calibrate automatic pipelines that determine atmospheric parameters of stars, one needs a sample of stars, or "benchmark stars", with well-defined parameters to be used as a reference. Aims: We provide detailed documentation of the iron abundance determination of the 34 FGK-type benchmark stars that are selected to be the pillars for

Following a vast search for extended Planetary Nebulae (PNe) in the Galactic Plane using IPHAS, we present the first release of the "IPHAS Catalogue of Extended Nebulae". The catalogue in its current version contains more than one hundred spectroscopically identified PNe distributed from the Galactic Center to the Galactic Anticenter. These new

The Solar System with its variety of planets and minor bodies, is it an exceptional entity in the universe, or is it perfectly normal to find planets orbiting around stars? Until the announcement of 51~Pegasi~b in 1995---the first solid discovery of a planet orbiting a main-sequence star other than Sun---the first answer was considered the most

Both meteorology and optical conditions are crucial for selecting the best site to host extremely large telescopes such as the Thirty Meter Telescope (TMT) and the European project (E-ELT). For the E-ELT, a year-long meteorological campaign was performed at our two reference sites, the Observatorio del Roque de los Muchachos (ORM) and Cerro

The Apache Point Observatory Galactic Evolution Experiment (APOGEE)—one of the Sloan Digital Sky Survey III programs—is using near-infrared (NIR) spectra of ~100,000 red giant branch star candidates to study the structure of the Milky Way. In the course of the survey, APOGEE also acquires spectra of hot field stars to serve as telluric calibrators