Showing papers on "Polarimetry published in 1969"
TL;DR: In this article, a new design for the exit slits of the Locarno polarimeter is described, which avoids the ambiguities in the determination of the magnetic field vector that always occur when using two exit sits.
Abstract: The miscentering by the Doppler compensator of the Locarno polarimeter is investigated in detail. It is shown that the linear polarization is strongly falsified by this effect which also occurs at the Crimean and Izmiran polarimeters.The new design for the exit slits of the Locarno polarimeter is described. It avoids the ambiguities in the determination of the magnetic field vector that always occur when using two exit slits.A new simple electronic setup avoids most of the difficulties which are usually involved in eliminating instrumental polarization and compensating intensity fluctuations.The observational techniques for solar polarimetry at the Locarno observatory are described.To avoid mutual influences of V and U, the line centre λ0 (corresponding to V = 0 and U = max.) must coincide with the centre of slit II. Only in this case we have 234-01
20 citations
TL;DR: In this paper, the Stokes parameters of linearly polarized atmospheric visible radiation in four narrow spectral regions are measured using a polarizing prism assembly of four Glan Thompson prisms oriented so as to transmit light vibrations at 0°, 45°, 90° and 135° with respect to a chosen direction.
Abstract: A new polarimeter, to measure the Stokes parameters of linearly polarized atmospheric visible radiation in four narrow spectral regions, is described. The instrument was developed for airborne application to measure polarization of reflected solar radiation from various land, sea and cloud surfaces. It consists essentially of a polarizing prism assembly of four Glan Thompson prisms oriented so as to transmit light vibrations at 0°, 45°, 90° and 135° with respect to a chosen direction. A rotating aperture wheel allows the light beams transmitted by the polarizers to reach the cathode of a photomultiplier tube in sequence. The signals from the photomultiplier tube are separated and identified with gate circuits triggered by pulses from magnetic transducers fixed near the polarizing prisms. From simple relations between the output signals the desired Stokes parameters are obtained. The transducer pulses are also passed through delay circuits to give delayed pulses to gate housekeeping data such as spectral region, optical gain, scan angle, etc. The method of measurement and some results obtained during a recent meteorological expedition are presented.
5 citations