European Southern Observatory New Technology Telescope

General :
Observations :
Operations :

Echelle Setup

Introduction: there are 3 main modes in Echelle :

• Echelle classic: Echelle + X-disperser + Mask (if needed)
• Echelle "long slit + X-disperser" ( no mask)
• Echelle "long slit + filter" (no X-disperser, no mask)

To setup an ECHELLE grating:

• Install requested cross disperser grism(s) in position #6 or (/and) #7 of grism wheel.
• For Ech #10 or #14, install Echelle mask in REMD path unless not wanted by observer ( e.g. long slit).
• For Ech#9 do not use Echelle mask in REMD.
• On EMMI configuration panel declare echelle , echelle mask and cross disperser(s) status.
• Although the status on EMMI config panel remains "not centered ",

Echelle is in the proper position and does not need centering.
• Click Backup under File submenu.
• Focussing: run REMD_all_tec_SetFoc to tune focus formula, then:
  • if cross disperser will be used, run REMD_all_tec_CheckFoc
    without cross disperser (as template doesn't work with it)
    and choose the option Fixed focus or focus offset according to request.
    
  • if long slit mode (narrow band filter and no cross disperser) is requested:
    run REMD_all_tec_CheckFoc with specified filter and no grism.
    • long slit mode filters are generally so narrow that exposure time above 300 s is recommended.
      this means that focus check will last 40 mn at least.
      
• The best focus temperature will be automatically reported into the REMD focus popup window.
  You can verify it in the next REMD_ech_cal_Arcs for instance. (Be careful if two cross dispersers are going to be used: only the last measured best focus will be recorded automatically).
  
• Leave the corresponding focus curve print out on wemmi keyboard.
• For Echelle#9 , run a wave calibration REMD_ech_cal_Arcs  with parameters:
•          Slit width SLIT.WID = 1".0
•          Slith length SLIT.LEN = 10".0
•          lamp  LAMP1.NAME Th
•          time  LAMP1.EXPTIME ~ 120 sec.
•          GRAT.NAME = Eche#9.
• Compare the RTD display to the figure which you can find in

Emmi Users's Manual section C.4.

Send comments to: NTT Webmasters <nttweb@www.eso.org> Last Update: MMM DD, YYYY (WHO)