The experimental study of sodium layer is relevant to fields such as adaptive optics, in particular for laser guide star generation. We have developed an instrument to make systematic measures of the most relevant parameters of the sodium layer above canarian observatories. The measurement provides information about sodium layer: the medium

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A new generation of instrument using a launching laser is been developed to correct the atmospheric image blurring and to establish optical communication with space. Then, light pollution generated by laser will be a serious operational problem in next years. This laser could affect astronomical works of adjacent telescopes when the laser lay

K 4-47 is an unusual planetary nebula (PN) composed of a compact high-ionization core and a pair of low-ionization knots. Long-slit medium-resolution spectra of the knots and core are analyzed in this paper. Assuming photoionization from the central star, we have derived physical parameters for all the nebular components, and the ionization

We present the image and catalogue of the 14.3 μ shallow survey of 0.55 square degrees in the region of the Lockman Hole (10^h52^m03^s +57°21'46'', J2000) with the Infrared Space Observatory (ISO). The data have been analyzed with the recent algorithm by Lari et al. (cite{Lari01}, MNRAS, 325, 1173) conceived to exploit ISO data in an optimal way

We derive accurate values of the orbital parameters of the close binary β Cephei star λ Scorpii. Moreover, we present the first determination of the properties of the triple system to which λ Scorpii belongs. Our analysis is based on a time series of 815 high-resolution spectra, covering a timespan of 14 years. We find a close orbit of 5.9525 d