An automatic and fast procedure was implemented to determine Te and log g from the comparison of the UV S 2/68 spectra with the Kurucz models. The method has been applied to all A and F stars with (B-V)0 greater than or equal to 0 and luminosity classes III, IV, IV-V, and V, included in the Ultraviolet Bright-Star Spectrophotometric Catalogue. From

Calculations of atmospheric transmission through the M (5 microns) atmospheric window, at a resolution of 10 to the 3rd power are presented for sites at the Observatorio del Teide, Tenerife and the NHO, La Plama in the Canary Islands. We use a standard midlatitude atmospheric model and absorption line strengths for the known molecular species

The 2(1,1) - 2(1,2) rotational transition of HDO has been detected towards the KL position at the center of the OMC-1 at a velocity of +5.5(+ or - 1.3)km/s, corresponding to emission from the central core. This measurement is combined with previous estimates of the H2O abundance close to KL to obtain a ratio of the concentration of HDO to that of

Position data of sunspot groups from the period 1874-1902 are used to investigate the differential rotation of the Sun and the meridional motions of the sunspots. The equatorial velocity is higher than in the period 1940-1968 investigated by Balthasar and Wöhl (1980), while differences between the northern and southern hemispheres are less. For

The 1-8A band of synodic full-disc solar X-rays (1-8A) W/m(2) were measured nearly continuously from 1975 to 1981 aboard the SMS-1, SMS-2, GOES-1, GOES-2, and GOES-3 satellites. The 1-8A band of X-rays are proportional to the emission measure at coronal heights at temperatures greater than 2,000,000 K. A practical method of describing solar 1-8A

The IUE observed AB Aur, HD250550, and BD + 46 deg 3471 at high resolution in the range 2000 to 32000 A. The MgII resonance line profiles all show a P Cygni structure, with an intense emission, and a shortward wing velocity in the absorption component of 300 to 600 km/sec. In HD 250550, the Fe II line spectrum exhibits a shell phenomenon: all lines