We present internal proper motion measurements of more than five hundred positions of NGC 2392, based on images acquired with the WFPC2 on bord of the Hubble Space Telescope for two epochs separated by 8.805 yr. We measured the amount of motion of local structures in the nebula determining their relative shift during that interval. We compared two

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