European Southern Observatory New Technology Telescope

General :
Observations :
Operations :

EMMI - REMD Focus Flexure Monitoring

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

The procedure takes n exposures of a 1"x3.2" slit  seen through Focus Wedge , changing the rotaror angle by a rotator step editable in the Remd_tec_Flexure.obd, then, measures the displacement of the image on the CCD in x and y directions for the leftmost image and dy ( defocussing)  for the rightmost image
( x axis is along the dispersion and y axis is across the dispersion ).

The RemdTiFlexure.seq template moves rotator b from wemmi.

Procedure:

• If no echelle is mounted verify that the grating you are going to use is centered
• if not , center it with REMD_spec_tec_CenterGrat.obd of the proper grating.
• Load Remd_tec_Flexure.obd in BOB :
• Update, if you have time ,  the rotator step angle to 30 .
• Update Grating name : possible names are:
• Grat#6
• Grat#7
• Grat#8
• Grat#13
• Eche#9
• Eche#10
• Eche#14
• Mirr#2
• ( if you have time it's good to test both grating of the support)
•  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, adjust boxsize to about images

separation, click lower then upper 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 2 printouts and store them into maintenance result binder
• Compare to previous  results and report any significant variation .

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