Presented is a brief guide to the maps of Mars which contain the Viking 1 and Viking 2 landing sites. Included are maps and photomosaics originally produced at the following scales: 1:25 million, 1:15 million, 1:5 million, 1:2 million, 1:1 million, and 1:250,000. In each case the Viking locations are indicated on the maps and photomosaics.

The very high surface gravity and low temperature of PHL 932, a hot subluminous star surrounded by a planetary nebula, imply that it cannot be a post-AGB star. It thus becomes the second object of this kind discovered spectroscopically. The spectroscopic evidence is presented, and some properties of the nebulae around these two stars are inferred

The "line ratio method" (Stenflo, 1973) has been extensively used in the past to carry out measurements of the magnetic field strength in spatially unresolved magnetic flux concentrations. The authors present here a new variant of this technique, which is particularly simple as it does not depend on any radiative transfer calculations and thus the

Spectrograms of a sample of nitrogen-rich early type stars (OBN stars) are analyzed differentially to normal stars of similar spectral types by means of NLTE methods. Effective temperatures, gravities and atmospheric helium contents are derived by fitting theoretical profiles of hydrogen and helium lines to the observations. The abundance analysis

The combined UV and optical spectrum of the Seyfert type 2 galaxy NGC 3393 is presented and analyzed together with published IR and IRAS data. The conditions in the narrow-line gas strongly suggest that the high-ionization material is in a zone of higher density (Ne = 100,000/cu cm) while the low-ionization material is at Ne = 1000/cu cm. No

The authors present the results of a statistical analysis of the penumbra of sunspots. The intensity distribution, and several parameters derived from it, is analysed at different heliocentric angles and positions on the spot. It has revealed, on the one hand, that a two-component model is compatible with the observations and that both components