European Southern Observatory New Technology Telescope

General :
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.

Procedure:

Verify that the grating you are going to use is centered

• if not , center it with BLMD_spec_tec_CenterGrat.obd of the proper grating.

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

• no interlock is on
• M3 is looking side B

 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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