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Observations :
Operations :

EMMI - BLMD Flexure Monitoring


The purpose of this procedure is to monitor the mechanical flexures produced  into EMMI - BLMD with the rotator at different angles measuring the shifts of image on CCD in x,y.

The procedure takes n exposures of a 1"x3.2" slit changing the rotaror angle by a rotator step editable in the Blmd_tec_Flexure.obd, then, measures the displacement of the image on the CCD in x and y directions.
( x axis is along the dispersion and y axis is across the dispersion ).

To control rotator from wemmi , the Blmd_tec_Flexure.seq script must simulate  telescope presets.


  • Verify that the grating you are going to use is centered
  • Load Blmd_tec_Flexure.obd in BOB :
  • Modify Grating name in BOB if necessary.
  • Update grating name and, if you wish,  the rotator step angle :
  •  Check that rotator may rotate safely :

  •   it is advised to keep light on in EMMI room and switch camera video watching to EMMI.
  • Check that
  •  Start template in BOB

  • After first exposure, in MIDAS/PCO display window, click image, then click twice mouse middle button.
  • check that rotator is moving from -180 degreed to 180 degrees and back stepwise.
  • At completion pick up print out, check it and store it in maintenance result binder
  • Compare to previous  results and report any significant variation .

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