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General :
Observations :
Operations :


Procedure :
   Grism and Slit Alignments 
Author :
   SOFI team
Release :
  17/01/04 : update   M. Billeres
 06/01/99 : creation
 
 

The alignment of the SOFI slits and grisms should be checked each time that a SOFI run starts. They should also be checked when the instrument has been thermally cycled. The stepper motor values for both grisms and slits are kept in the file /vlt/insroot/SYSTEM/MISC/ICS/isiInstrumentSOFI.cfg.

Checking the Alignment:

  • From wa5tcs, set the absolute rotator angle to zero. This can be done by presetting to Zenith, if the telescope state is ONLINE, or by sending the command PRESET abs,0,200 to the process rotServer on lt5ra, if the telescope is state is STANDBY. In the latter case, the state of the TCS module nttrot A needs to be ONLINE.
  • Make sure MIDAS for PCO is running on wsofi.
  • From the directory /data/INSROOT/SOFI/SYSTEM/COMMON/OBD/CALIB/, load either the template SOFI_spec_tec_AlignSlit.obd (align slits) or SOFI_spec_tec_AlignGrism.obd (align grisms) into Bob.
  • The Calibration Unit must be in, however for the slit alignment the background light in the Ks filter is enough and the calibration unit is not necessary. For the grism allignment the calibration unit must be in and lamp 1 must be on,  around 30.
  • The results are recorded in the files /vltdata/SPC/Sofi_spec_tec_AlignGrism.SPC and /vltdata/SPC/Sofi_spec_tec_alignSlit.SPC.
  • If the alignment is better than 1 pixel per 1000 pixels, do nothing and stop here. If the alignment is worse, run the template again. If it is still worse, the default stepping motor position will need to be adjusted.

    • Editing the Configuration File:

  • Bring up the ICS control panel from the tools menu of the OS panel.
  • From the commands menu of the ICS panel set all devices OFF. The name tags of instrument functions will turn red.
  • Bring up the configuration tool from the tools menu of the ICS panel.
  • Select the file isiInstrumentSOFI.cfg from the configuration tool, edit it : an emacs window will be opened will all the values for all the encoder positions.
  • Make the appropriate change : 

    • For the grismes:

    INS.F5.MAC4-POS1
    		 
    88583;
    		 
    # Wollaston
    		 
    INS.F5.MAC4-POS2
    		 
    123957;
    		 
    # Grism Blue
    		 
    INS.F5.MAC4-POS3
    		 
    157492;
    		 
    # Grism Red
    		 
    INS.F5.MAC4-POS4
    		 
    193050;
    		 
    # Focal Elongator
    		 
    INS.F5.MAC4-POS5
    		 
    225755;
    		 
    # High Resolution Grism
    		 
    INS.F5.MAC4-POS6
    		 
    258467;
    		 
    # -Echelle Red
    		 
    INS.F5.MAC4-POS7
    		 
    292623;
    		 
    # -Echelle Blue
    		 
    INS.F5.MAC4-POS8
    		 
    57627;
    		 
    # Open


    For the slits :

     
    INS.F1.MAC4-POS1
    		 
    102400;
    		 
    # JG Encoder step for position i
    		 
    INS.F1.MAC4-POS2
    		 
    141161;
    		 
    # ech1 Encoder step for position i
    		 
    INS.F1.MAC4-POS3
    		 
    165915;
    		 
    # ech2 Encoder step for position i
    		 
    INS.F1.MAC4-POS4
    		 
    222399;
    		 
    # SF Encoder step for position i
    		 
    INS.F1.MAC4-POS5
    		 
    262630;
    		 
    # Pol Encoder step for position i
    		 
    INS.F1.MAC4-POS6
    		 
    302375;
    		 
    # LF Encoder step for position i
    		 
    INS.F1.MAC4-POS7
    		 
    341450;
    		 
    # HR Encoder step for position i
    		 
    INS.F1.MAC4-POS8
    		 
    382656;
    		 
    # 2 Encoder step for position i
    		 
    INS.F1.MAC4-POS9
    		 
    22757;
    		 
    # 1 Encoder step for position i
    		 
    INS.F1.MAC4-POS10
    		 
    63036;
    		 
    # 06 Encoder step for position i

    Quit the emacs window saving the new values.

  • Press the load button and wait about 20 seconds for a window with an OK to appear.
  • From the commands menu of the ICS panel, set the instrument mode to STANDBY. The name tags of instrument functions will turn green.
  • From the commands menu of the ICS panel, set the instrument mode to ONLINE. The name tags of instrument functions will turn purple as each function is initialised.
  • Quit the configuration tool and ICS panels.
  • Archive the configuration file.

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    Last Update: January 17, 2004 (Malvina Billeres)    		 [ESO][ESO][ESO][Search][Help][News]