We present outburst spectroscopy of GX 339-4 that may reveal the motion of its elusive companion star. N III lines exhibit sharp emission components moving over ~300 km s-1 in a single night. The most plausible interpretation of these components is that they are formed by irradiation of the companion star and the velocities indicate its orbital

Chemical abundance data for the Galaxy show a wide dispersion. We try to check if this dispersion may also be found with chemical evolution models as an effect of variations of an Initial Mass Function (IMF) which follows a Poisson's distribution

Discontinuities in the wavefront phase or amplitude affect curvature sensor (CS) response. These discontinuities may be the result of an improper alignment of the elements of a segmented mirror in either piston or tip-tilt. We describe the CS response with an analytical approach based on the Fresnel approximation of the diffracted field and show

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Comet 21P/Giacobini-Zinner was observed from Nov. 8 to Dec. 10, 1998. Pre- and post-perihelion CCD images of the gas (CN, C2) and dust (green and red continua) coma were obtained with the 82 cm IAC-80 telescope at Teide Observatory (Canary Islands, Spain). For vp =0.85 rH-0.5 and vd = 1.19 km s-1 (i.e. characteristic of HCN being the CN parent

It is foreseen that Extremly large telescope (ELT) will include Adaptive Optics Systems to provide diffraction-limited images in the near infrared. The preliminary atmospheric turbulence properties which affects laser guide star (LGS) generation are presented here. The results of modern model developed in optical communication through atmosphere is