Sunrise is a light-weight solar telescope with a 1 m aperture for spectro-polarimetric observations of the solar atmosphere. The telescope is planned to be operated during a series of long-duration balloon flights in order to obtain time series of spectra and images at the diffraction-limit and to study the UV spectral region down to ~200 nm, which

In this contribution, the main characteristics of near infrared spectropolarimetric measurements are described, putting especial emphasis on the techniques to minimize the crosstalk between the Stokes parameters.

In this paper, we study the ability of a curvature sensor (CS) to measure co-phasing errors in a segmented primary mirror. We study a new fast and low memory-consuming algorithm based on the definition of an integrated curvature signal. This signal results from the integration of the CS response in enclosures matching the shapes of the segments in

An experimental Adaptive Optics system utilizing a low-altitude Rayleigh Laser Guide Star is presented. The current status of the project is described together with plans for future work, with the ultimate goal of providing demonstration Rayleigh LGS AO science on the 4.2m William Herschel Telescope. The implementation of the demonstration system

The spectra of two early B-type supergiant stars in the Sculptor spiral galaxy NGC 300 are analyzed by means of non-LTE line-blanketed unified model atmospheres, aimed at determining their chemical composition and the fundamental stellar and wind parameters. For the first time, a detailed chemical abundance pattern (He, C, N, O, Mg, and Si) is

This presentation reports the numerical simulations we have done in order to evaluate the performance of the first-light AO system of LBT. The simulation tool used for this purpose is the Software Package CAOS, applicable for a wide range of AO systems and for which a brief recall of the main features is made. The whole process of atmospheric