CFHT operating manual - Homepage Usask

ESPaDOnS: picture gallery http://webast.ast.obs-mip.fr/magnetisme/espadons_new/gallery.html
estimating the sky background (in the ’object+sky’ spectroscopic mode only); photons that do not enter the instrument
are reflected off towards the viewing/guiding channel;
detailed view of drawer 1 once removed from the main structure and taken from above,
showing both the adc slice and the rotation mechanism for the top adc prism (before optics was installed); the rotation
mechanism for the second adc prism is on the other side of the drawer;
detailed view of drawer 2 taken from below, showing the calibration wheel whose different
positions correspond to different sorts of illumination, the open space being for observations on the sky; optical parts
were not yet mounted at the time the image was taken;
close-up view of the lower part (polarimeter) with drawer 3 (first half-wave rhomb), drawer 4
(quarter-wave rhomb) and drawer 6 (with the fabry-perot wheel on one side and the wollaston/wedge plate slide on the
other side) installed, and drawer 5 (second half-wave rhomb) removed to improve visibility; the two microcontrol
barrels holding the two reimaging triplets are visible (at the top and bottom of the image), as well as the on-axis torque
motor rotating the half-wave rhomb (on drawer 3) and the fabry-perot wheel with associated temperature sensor (on
drawer 6);
detailed view of drawer 3 taken from below and showing the encoder disk (glued on the non
visible side of the central black disc) associated with the on-axis torque motor, the encoder sensor (metallic sector just
above the encoder sector) as well as the encoder electronics (small circuit board inserted in a rectangular holder at the
top of the image); the half-wave rhomb (to be inserted in the central cylindrical aperture) is not yet mounted;
close-up view of encoder circuit board on drawer 3;
detailed view of drawer 6 taken from above and showing the fabry-perot wheel (with no optics
inside) and its temperature sensor;
the fibre bundle coming out of the polarimeter, and conveying photons from the Cassegrain
module down to the spectrograph module;
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