Book contents
- Frontmatter
- Contents
- List of illustrations
- List of tables
- Preface
- Acknowledgements
- 1 Introduction
- 2 A description of polarized radiation
- 3 Polarization in astronomy
- 4 Polarization algebra and graphical methods
- 5 Instruments: principles
- 6 Instruments: implementations
- 7 Case studies
- Exercises
- Hints for exercises
- References
- Index
- Frontmatter
- Contents
- List of illustrations
- List of tables
- Preface
- Acknowledgements
- 1 Introduction
- 2 A description of polarized radiation
- 3 Polarization in astronomy
- 4 Polarization algebra and graphical methods
- 5 Instruments: principles
- 6 Instruments: implementations
- 7 Case studies
- Exercises
- Hints for exercises
- References
- Index
Summary
In this final chapter, several original papers from the literature are introduced, primarily as illustrations of modern instrumentation. The focus of this book being the measurement of polarization, the astronomy involved was a secondary consideration in selecting these particular papers from the wide range available. Readers are urged to test their grasp of polarimetric fundamentals by selecting a dozen or so further papers from those listed in the subject index of the more recent volumes of Astronomy and Astrophysics Abstracts under ‘polarimeters’, ‘polarimetry’ or ‘polarization’.
Multi-channel optical polarimetry using photomultipliers
A suitable example of optical polarimetry by the ‘classical’ technique of 100 Hz modulation and photomultiplier detectors is given in Können and Tinbergen (1991) and Können et al. (1993). It concerns an attempt to detect ice crystals in the upper parts of the Venus atmosphere by using the polarization peak at the 22° halo angle as a diagnostic. A large body of earlier Venus polarimetry exists, and scientific results derived from it are reviewed in Van de Hulst (1980, section 18.1.5 and references therein).
The terrestrial 22° halo and related phenomena owe their polarization to birefringence of the ice crystals that produce the halo. These crystals operate as 60° prisms, deviating the light from the Sun by an amount depending on the refractive index of the ice, hence by an amount which depends on the polarization of the light.
- Type
- Chapter
- Information
- Astronomical Polarimetry , pp. 125 - 131Publisher: Cambridge University PressPrint publication year: 1996