An analysis of about 27 h of fast photometry of the cool ZZ Ceti white dwarf PG2303+243 reveals (1) the presence of many modes (as many as 22), some of them of low enough amplitude to have escaped previous detection, and (2) a short time scale (less than 10 d) drastic variation in amplitude. A preliminary identification of the modes observed in

The paper analyzes white-light images of solar granulation taken outside active regions, at regular intervals along the polar axis and the equator, in order to study its center-to-limb variation and possible changes with the solar latitude. The 2D spatial power spectra of the brightness distribution are calculated and corrected for the distortions

We present a rigorous approach to the problem of the random clustering of points in one-dimensional Poissonian distributions. Exact expressions for the probability density of clusters are derived, and the statistical properties of the inner configuration of their associated structures are studied in detail. We review previous works in the field

A sensitive observing system for observing the cosmic microwave background on an angular scale of 8 deg is described. This angular scale is appropriate for studies of intrinsic fluctuations in the CMB generated by gravitational potential fluctuations (the Sachs-Wolfe effect). The beam-switching system employs low-noise and broadband cryogenically

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IAUC 5634 available at Central Bureau for Astronomical Telegrams. IAUC 5634 available at Central Bureau for Astronomical Telegrams.