MAGIC, a system of two imaging atmospheric Cherenkov telescopes, achieves its best performance under dark conditions, i.e. in absence of moonlight or twilight. Since operating the telescopes only during dark time would severely limit the duty cycle, observations are also performed when the Moon is present in the sky. Here we develop a dedicated

The European Solar Telescope (EST) is a European collaborative project promoted by the European Association for Solar Telescopes (EAST) to build a high resolution 4m class solar telescope in the Canary Islands. Since 2008 to 2011 a Design Study has been developed to define the Conceptual Design of EST. During the Design Study, several preliminary

This paper investigates the distribution of linear polarization signals in the quiet-Sun internetwork using ultra-deep spectropolarimetric data. We reduce the noise of the observations as much as is feasible by adding single-slit measurements of the Zeeman-sensitive Fe I 630 nm lines taken by the Hinode spectropolarimeter. The integrated Stokes

This publication utilizes photographs taken by NASA spacecraft, and cartographic products based on these photos, to illustrate size comparisons of the planets and moons of the solar system. It depicts both global views and prominent geographical features at the same scale, allowing size relationships to be studied visually.

We discuss the effects of collisional enhancement of Balmer lines on the determination of the primordial helium abundance. To this aim, we present a photoionization model of the metal-poor extragalactic H 0 region SBS 0335-052. We show that the derived helium abundance (Y) of this H 0 region depends on the amount of collisional excitation affecting

In this paper we present the second and final part of a large and photometrically homogeneous CCD color-magnitude diagram (CMD) data base, comprising 52 nearby Galactic globular clusters (GGC) imaged in the V and I bands. The catalog has been collected using only two telescopes (one for each hemisphere). The observed clusters represent 75% of the