Since the beginning of 1990, a sodium based resonance scattering spectrometer belonging to the IRIS Network has operated at Observatorio del Teide side by side with the MkI instrument (a resonance scattering spectrometer based on potassium) from the University of Birmingham and operated since 1975. A 3 month series of simultaneous data obtained in

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We present here the results of the second multisite campaign of the STEPHI (STEllar PHotometry International) network. This three weeks rapid photometry campaign is devoted to the Delta Scuti star GX Peg. Observations, data reduction and analysis are described. Multiperiodicity is shown and five frequencies are unambiguously detected.

Two years after its outburst in 1989, the William Herschel Telescope has been used to find absorption features in V404 Cyg characteristic of a late G or early K star with a radial velocity curve of amplitude 211 +/- 4 km/s and period 6.473 +/- 0.001 days. The deduced mass function of 6.26 +/- 0.31 solar masses is a firm lower limit to the mass of

We describe an experiment aimed at diffraction-limited imaging of astronomical sources in the 2-5/micron range. It is based on a rotation shearing interferometer that extracts the complex degree of coherence of the wavefront directly in the pupil plane. Interference fringes are produced by a Michelson interferometer in the image of the telescope

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