The solar vector magnetograph of the Okayama Astrophysical Observatory
Abstract
The vector magnetograph of the Okayama Astrophysical Observatory is fed to the 65 cm solar coude telescope with a 10 m Littrow spectrograph. The polarimeter put at the telescope focus analyzes the incident polarization. Photomultipliers (PMT) at the exit of the spectrograph pick up the modulated light signals and send them to the electronic controller. The controller analyzes frequency and phase of the signal. The analyzer of the polarimeter is a combination of a single wave plate rotating at 40 Hz and a Wallaston prism. Incident linear and circular polarizations are modified at four times and twice the rotation frequency, respectively. Two compensators minimize the instrumental polarization, mainly caused by the two tilt mirrors in the optical path of the telescope. The four photomultipliers placed on the wings of the FeI 5250A line give maps of intensity, longitudinal field and transverse field. The main outputs, maps of intensity, and net linear and circular polarizations in the neighboring continuum are obtained by the other two monitor PMTs.
- Publication:
-
Measurements of Solar Vector Magnetic Fields
- Pub Date:
- May 1985
- Bibcode:
- 1985svmf.nasa..173M
- Keywords:
-
- Doppler-Fizeau Effect;
- Polarimeters;
- Solar Magnetic Field;
- Spectrographs;
- Stokes Theorem (Vector Calculus);
- Vectors (Mathematics);
- Frequency Shift;
- Photomultiplier Tubes;
- Polarization;
- Instrumentation and Photography