Our first photoelectric magnetograph was built on the basis of a device supplied by our colleagues from the Siberian department of the Soviet Academy of Sciences in 1968. Our project of the measurement of magnetic fields was developed and organized by dr. Vaclav Bumba, DSc.
The device was a scanning photoelectric magnetograph for the measurement of the longitudal component of the magnetic field. It was based on a principle of the measurement of distances of s-components of the magnetically sensitive spectral line which is split by the Zeeman effect. Polarized light of both s-components were sinusoidally modulated by an electrooptical modulator with the KDP (Potassium Di-hydrogen Phosphate) crystal. Because of Soviet occupation of Czechoslovakia in 1968 the assembly of this device was not finished.
The magnetograph and its horizontal telescope was finished and put into operation in 1972 by dr. Miroslav Klvana.
|
|
|
| ||
Horizontal telescope:
Primary mirror of the coelostat (1) F = 540 mm, F = „
Secondary mirror of the coelostat (2) F = 540 mm, F = „
Objective (3) F = 440 mm, F = 35 m
The auxiliary plain mirror of the telescope (4) F = 430 mm, F = „
Pointing automaton with 1 arcsecond precision
Scanning automaton with 0.25 arcsecond escapement, max. speed 235 arcsecond/s
Grating spectrograph:
Entrance slit of the spectrograph (5) 0.5 mm (width) x 0.8 mm (height)
Collimator (6) F = 260 mm, F = 960 mm
Grating (7)
Camera mirror for photoelectric work (8b) F = 320 mm, F = 900 mm
Secondary slits of the magnetograph (9b)
Physical quantities measured by the magnetograph:
Longitudal component of the magnetic field - sensitivity about 50 Gauss
Brightness intensity in the spectral continuum - sensitivity about 1% of the intensity in the centre of the solar disk
Doppler velocities were not able to be measured (instability of the line in spectrograph)
Amount of observations in single years:
1972 - 45 1973 - 65 1974 - 57 1975 - 49 1976 - 11 1977 - 40
1978 - 39 1979 - 39 1980 - 46 1981 - 62 1982 - 13 1983 - 62
Data output was on registration paper in 1972-1973
Data output was on punched tape in 1974-1983
Necessary time for measurement of 300x200 arcsec area was about 1 hour