The monitoring of the column density of atmospheric sodium could be crucial for the efficiency of LGS systems. However, its detection is affected by the presence of water lines around the sodium doublet lines; this is really dramatic in the D2 line. We have developed a new method to detect the D2 sodium telluric line, obtaining previously the solar

We present a grid of theoretical models where the calculation of absorption line spectral indices in both the blue and red wavelength ranges is done with the same evolutionary synthesis code. We have computed some of these indices: CaT, Na i, Mg i in the near infrared and Mgb, Mg2, Fe52, Fe53, NaD and Hβ , in the blue-visible range, for Single

Stellar flare research is an exciting and rapidly developing field of astrophysics. The Sun is an invaluable proving ground to test predictions of flare theories and to develop analytical techniques for future stellar applications, because the lack of spatial resolution for stellar flares pushes us to extrapolate models of solar flares to the

We report YALO consortium observation of a mini-outburst of Aquila X-1 = V1333 Aql, which occurred between July 04.27 and 07.29 UT. This X-ray binary outbursts approximately once per year, and most recently entered a mini-outburst during May 2000 (IAUC 7423,7429). We have been monitoring this source since April 5 in R using the YALO 1-m telescope

The study of the stellar content and physics of the ionized gas in local high-mass star-forming regions is specially important for better understanding extragalactic starbursts. Recent observations from space telescopes and near-infrared detectors have provided a wealth of new information about the gas and stars in these objects. In this paper, I

Realistic ab-initio 3D, radiative-hydrodynamical convection simulations of the solar granulation have been applied to Fe i and Fe ii line formation. In contrast to classical analyses based on hydrostatic 1D model atmospheres the procedure contains no adjustable free parameters but the treatment of the numerical viscosity in the construction of the