We present narrowband imagery and long-slit intermediate-resolution spectroscopy of the multiple-shell planetary nebulae NGC 2438 and NGC 5882. A comparative study of the chemical abundances of the main nebulae and their surrounding halos shows a moderate N/O enrichment of the central regions. The oxygen abundances appear constant throughout the

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In a statistical analysis of Debrecen Photoheliographic Results sunspot area data we find that the logarithmic deviation (logD)' of the area decay rate D from the parabolic mean decay law (derived in the first paper in this series) follows a Gaussian probability distribution. As a consequence, the actual decay rate D and the time-averaged decay

We have monitored the photometric, spectroscopic and polarimetric variations of the classical T Tauri star (CTTS) AA Tau over a period of a month. The light curve consists of more than 260 measurements in each of the B and V-bands over a continuous time period of 30 days and more than 180 measurements in the R and I-bands. This provides

{A high-resolution, high signal-to-noise HIRES-Keck spectrum of APM 08279+5255 reveals a feature in the HI Lyalpha profile of the z_abs=3.514 absorber at the expected position of the corresponding DI Lyalpha line. The absorber shows a relatively simple velocity structure, with a major component detected in several metallic lines including CII, CIV

Time series of high-resolution white-light images of solar pores are analyzed. Granular motions in the vicinity of pores are driven by mesogranular flows: Motions toward the pore dominate in the 2 arcsec zone around the pore boundary, while at larger distances the granules move away from the pore. Triggered by these motions, small granules and