We determine the extinction curve in the zl=0.83 lens galaxy of the gravitational lens SBS 0909+532 from the wavelength dependence of the flux ratio between the lensed quasar images (zs=1.38) from 3400 to 9200 Å. It is the first measurement of an extinction curve at a cosmological distance of comparable quality to those obtained within the Galaxy

Doppler velocities in the penumbra of a δ-configuration sunspot observed near the limb indicate flows that converge upon the line separating locally positive and negative polarity magnetic field (the polarity inversion line). These flows persist for many hours. Observations of this region with the Advanced Stokes Polarimeter (ASP) reveal a convex

We have studied the Balmer line shapes of NGC 3516 in order to find the structure of central Emission Line Region (ELR) and the physical parameters of the emitting plasma. The shapes of these broad emission lines show evidences of a multicomponent origin and also features which could be identified as the peaks of a rotating disc. We have proposed a

The best-fitting two-dimensional plane within the three-dimensional space of spiral galaxy disc observables (rotational velocity vrot, central disc surface brightness μ0=-2.5logI0 and disc scalelength h) has been constructed. Applying the three-dimensional bisector method of regression analysis to a sample of ~100 spiral galaxy discs that span more

The IRIS network has been operated continuously since July 1st 1989. To date, it has acquired more than a complete solar cycle of full-disk helioseismic data which has been used to constrain the structure and rotation of the deep solar interior. However, the duty cycle of the network data has never reached initial expectations. To improve this

In the present work, we study correlations between stellar fundamental parameters and the oscillation amplitude for delta Scuti stars. We present this study for a sample of 17 selected delta Scutis belonging to 5 young open clusters. Taking advantage of properties of delta Scutis in clusters, we correct the photometric parameters of our objects for