High resolution H alpha and white light observation of the birth of 73 active regions (AR) were used to check models of sunspots. It is concluded that large AR result from the emergence of a compact and twisted flux rope, while the small ones are produced by the clustering of flux tubes by supergranular motions.

Potassium line data from observatories in Hawaii and Spain were used to establish the authenticity of complex solar oscillation signals. Combination of the two data sets yields precise frequency, amplitude and phase determinations. Analyses of individual lines indicate possible decay and excitation of individual modes and suggest lifetimes for the

The nonlinear development of the kink instability of a magnetic flux tube initially lying in mechanical equilibrium in the deep convection zone is presented. The unstable evolution is started by a small-amplitude sinusoidal perturbation of the shape of the flux tube in a vertical plane. As a result of the development of the instability, the lower

Single-epoch multifrequency data for the BL Lac objects OI 90.4 and 3C 66A, spanning radio through ultraviolet wavelengths, are presented, as well as other measurements relevant to intensity and spectral-shape variability. Both BL Lac objects exhibit spectral curvature in the infrared-to-ultraviolet region, a properity that is inferred to be usual

IUE spectra of Mg II h and k in late type dwarfs and giants were used to detect and measure absorption components due to the LISM. This technique gives a method of probing the awkward range from d = 3 pc to d = 80 pc from the Sun. In spite of interpretational uncertainties the HI component of the LISM can be plotted well enough to confirm it as a

Detection of narrow (δλ 0.5 Å) absorption features in C IV at λλ1548 and 1550 have been made in the spectra of 4 late B dwarfs within 200 pc of the sun; the Si IV doublet at λλ1393 and 1403 shows up in two of them. The authors argue that it is difficult to account for the strengths, widths, shapes, and C IV/Si IV ratios in terms consistent with a