The evolution of the emission line ratios of a photoionized cloud described by standard BLR parameters which is exposed to a varying ionizing continuum is studied. The hardness of the ionizing distribution was varied by decoupling the UV increase from that of the X-ray component. After many tests using various ionizing distributions, it became

IAUC 4830 available at Central Bureau for Astronomical Telegrams.

Optical spectroscopy, H-alpha interferometry, and near-IR mapping and photometry of the bipolar H II region S201 are reported. The observations are used to place constraints upon the energetics of the H II region as well as to provide a clearer understanding of the IR structure. The exciting star is coincident with a central bar of obscuring

A spectral ratio, similar to that of von der Lühe (1984), is proposed to derive information on the degradation of the mean granular power spectrum at a position outside the disk centre. It has the advantage that the modulation transfer function is obtained directly from the data, without making any assumption on turbulence theory to describe the

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