Results are presented of 2D radiative transfer calculations performed for geometric configurations that simulate partly evacuated small-scale magnetic flux sheets embedded in the ambient solar atmosphere. Temperature distributions in (gray) radiative equilibrium at low optical depths where radiation transfer dominates the energy budget are obtained

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

We present a first approach to systematic characterization and interpretation of observed asymmetries of Stokes profiles as a function of spatial position within sunspots. Spatial maps of the full Stokes profiles of Fe I 6302.5 A gathered in large sunspots using the HAO Stokes II instrument reveal asymmetries that vary systematically across large

An inversion code of Stokes line profiles is presented. It allows the recovery of the stratification of the temperature, the magnetic field vector, and the line of sight velocity through the atmosphere, and the micro- and macroturbulence velocities - which are assumed to be constant with depth. It is based on the response functions, which enter a

Infrared photometry of the WC7-type Wolf-Rayet star WR 125 (MR 93) in 1981-91 shows a 10-fold rise in the 3-4 micron flux during 1990-91. This, together with observations at longer wavelengths, is interpreted in terms of the condensation of dust in its wind, similar to the events observed from episodic dust-making WR stars like WR 48a in 1979-80

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