In this timely volume, the editors present eight specially-written chapters by experts renowned for their teaching skills. The chapters show how astronomers can deduce the internal composition (density, helium abundance, etc.) and dynamical structure (rotation, sub-surface velocity fields, etc.) of the Sun through helioseismology, and how

Narrow-band Hα+[NII] imaging and long-slit spectroscopy at intermediate resolution from [NeV] lambda3426 to [SIII] lambda9532 of the LINER galaxies NGC 4579 and 6500 are analysed. Both galaxies show circumnuclear emission, extending 2kpc from the nucleus of NGC 4579 in a loop structure and 1 kpc from the nucleus of NGC 6500 in a bright knot to the

This article presents narrow-band Hα and [OIII] images of the interacting pair of galaxies NGC 5953 (with a Seyfert type 2 nucleus) and NGC 5954 (with a LINER). Long-slit spectroscopy, from [NeV] lambda3425A to [SIII] lambda9532A, at intermediate resolution along position angles 44 deg and 182 deg through the nucleus of NGC 5953, is also presented

We describe statistical properties of complete samples of HII regions in the grand-design spiral galaxies NGC 157, NGC 3631, NGC 6764 and NGC 6951. We use the catalogues of HII regions obtained from high-quality Hα line images by Rozas et al. . Slopes and zero points of diameter distribution functions for these four galaxies coincide well with

We have observed 10 luminous blue stars in M 33 at intermediate dispersion and have determined spectral types and luminosity classes from the blue and red spectrograms by comparing with galactic and SMC stars. Halpha_ profiles have proved to be very useful in disentangling luminosity and metallicity effects, and constitute a valuable diagnostic

SU Ursae Majoris the prototype of a subgroup of dwarf novae that display superhumps in super- outbursts has been observed during an international campaign dedicated to the observation of the first day of outburst of dwarf novae during 1986 February. After the start of a brightening was reported, the star was monitored by IUE, ground-based