An attempt is made to explain conflicting experimental data recently obtained concerning the frequency stability of solar oscillations. Extensive data obtained at the Observatorio del Teide are analyzed to determine the lifetimes and frequencies of the l0 and l1 p-modes. The importance of the lifetime of the mode in determining the frequency is

CCD photometry of the M87 jet in the Thuan-Gunn r and g filters is presented. Accurate elliptical models of the underlying stellar emission were subtracted from the reduced and calibrated frames. The residual images show a number of morphological features not clearly seen before such as the faint extension at the end of the jet and faint red

A new phenomenological model for the interpretation of the discrete redshift phenomenon is developed. The model, based on the basic physical notion of adiabatic invariants and quantum conditions, similar to those used in the old quantum theory, leads to the same results as the spinor eigenvalue equation proposed by Cocke. The adiabatic principle

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