This paper describes the wave-front correction system developed for the Sunrise balloon telescope, and it provides information about its in-flight performance. For the correction of low-order aberrations, a Correlating Wave-Front Sensor (CWS) was used. It consisted of a six-element Shack - Hartmann wave-front sensor (WFS), a fast tip-tilt mirror

The VLT-FLAMES Tarantula Survey is an ESO Large Programme that has provided multi-epoch spectroscopy of over 1000 stars in the 30 Doradus region in the Large Magellanic Cloud. Armed with this unique dataset the assembled consortium is now addressing a broad range of fundamental questions in both stellar and cluster evolution. Here we give an

The first science flight of the balloon-borne Sunrise telescope took place in June 2009 from ESRANGE (near Kiruna/Sweden) to Somerset Island in northern Canada. We describe the scientific aims and mission concept of the project and give an overview and a description of the various hardware components: the 1-m main telescope with its postfocus

We briefly outline the scientific and instrumental aspects of ESA's Solar Orbiter mission. Special emphasis is given to the Polarimetric and Helioseismic Imager, the instrument with the highest relevance for helioseismology applications, which will observe gas motions and the vector magnetic field in the photosphere at high spatial and temporal

One of the main drawbacks in the analysis of the dynamics of the solar core comes from the lack of consistent data sets that cover the low and intermediate degree range (ell = 1,200). It is usually necessary to merge data obtained from different instruments and/or fitting methodologies and hence one introduces undesired systematic errors. In

We present inferences of the internal solar rotation rate and its evolution during solar cycle 23. A full solar cycle of MDI observations have been analyzed using an improved fitting methodology and using time series of various lengths, up to a single 4,608 day long epoch (64 times 72 days or 12.6 yr). We used time series of spherical harmonic