sun

First light for an astronomical 3-D photon detector.

Spectroscopic studies of extended astronomical sources at optical wavelengths are hampered by the two-dimensional nature of current photon detectors. Most photons of interest are not utilized because a spectrometer must scan in the spatial or …

Two-dimensional polarimeter with a charge-coupled-device image sensor and a piezoelastic modulator

Application of multiframe iterative blind deconvolution for diverse astronomical imaging

We present applications of a recently developed iterative blind deconvolution algorithm to both simulated and real data. The applications demonstrate the algorithm's performance for a wide range of astronomical imaging. We demonstrate the …

On the strength of solar intra-network fields.

The combination of the German Vacuum Tower Telescope and the prototype of ZIMPOL I (Zuerich Imaging Stokes Polarimeter I), a novel, very sensitive imaging polarimeter, has resulted in the first spectra of solar intra-network (IN) fields in circular …

Resolution of magnetic flux tubes on the Sun

Magnetic flux at the surface of the Sun is predominantly concentrated in discrete areas with kilogauss field strengths. Except for sunspots, these areas are too small to have been resolved by conventional observations. These magnetic flux tubes are …

Solar speckle polarimetry

The combination of a polarimeter with real-time frame selection and differential speckle imaging results in diffraction-limited magnetograms that provide new insight into the morphology of solar small-scale magnetic fields. The method to record …

High Spatial Resolution Magnetograms of Solar Active Regions

Using the Universal Birefringent Filter at the Sacramento Peak Vacuum Tower Telescope we have obtained simultaneous observations of left and right circular polarization in various solar magnetic features with a resulting spatial resolution of 0''.7 …

Multicolor Continuum Analysis of the Solar Granulation in Quiet and Active Regions

A set of narrow-band filtergrams of the solar photosphere recorded in three widely separated true continuum windows and in Mg I b1 with a spatial resolution of about 0.5 arcsec is analyzed. The influence of small-scale magnetic fields on the …

Dependence of the properties of solar magnetic flux tubes on filling factor. II - Results of an inversion approach

The dependence of the properties of solar magnetic elements on the magnetic filling factor is studied using Stokes V spectra of three lines observed near the center of the solar disk. The inversion technique developed by Keller et al. (1990) is …

Solar magnetic field strength determinations from high spatial resolution filtergrams

Circularly polarized images with high spatial resolution (better than 1 arcsec) of a solar active region, obtained with a tunable filter in the wings of Fe I 5247.1 A and Fe I 5250.2 A, have been analyzed in terms of the magnetic line ratio technique …