1. Starting the system
2. LIRIS real time display (RTD)
3. LIRIS mechanisms
4. Focusing
5. LIRIS observing commands
6. End of night
7. Shutting down the system
8. Writing data tapes
9. Important notes
    

6. End of night

It is not necessary to shut down the observing system at the end of the night.

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7. Shutting down the system

• Put LIRIS to sleep:
  SYS> lsleep
  
• Shut down the system computer:
  SYS> shutdownobssys
  on the pink window and wait until the prompt is back. Most of the windows will disappear (the RTD, log, mechanism mimic, array info window, talker, identify window).
  
• Shut down the DAS on the DAS orange window corresponding to LIRIS and wait until the prompt is back:
  DAS> shutdownobssys
  
• Close the TCS display window manually: from the File menu, select Exit .
  
• Close the Ximtool window: from the File menu, select Quit .
  
• Log out of LIRIS's control computer: click the right mouse button on the background screen and select Exit.

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8. Writing data tapes

• Get a DAT tape from the box located in the terminal area of the WHT, and fill in your initials, date, etc in the folder.
• Put the DAT tape in the DAT drive in lupus (in the terminal area).
• Open up an xgterm.
• cd /obsdata/wht?/yyyymmdd
  
• There are two options:
  • Use tar to write the data tape, e.g.
    tar -cvf /dev/rmt/0lbn .
  • Alternatively:
    fitsinit   (follow the instructions and answer the questions), then
    fitsout  (follow the instructions and answer the questions).
    

NOTE: If you wrote the data tape with fitsinit / fitsout, use the mscrfits command in the mscred IRAF package for reading the data. This is necessary because LIRIS images are multi extension images.

Previous: 5. LIRIS observing commands

9. Important notes

• If for any reason a failure occurs when running an observing script, slew the telescope to the object position and restart it again.
• If the RTD control panel disappears, type the following in the pink window:
  SYS> startrtd&
• The orientation in the LIRIS images is North up and East left when the rotator position angle is 0 degrees. Ask the TO (telescope operator) if you need different sky position angles (e.g. for long slit positioning).
• Take dark frames always with the same exposure time as your images. Darks should in general not be scaled to a different exposure time, since you scale the read noise then, too. In addition, non-linearities can be present.
• To take darks:
  
  • In the IRAF session and within the LIRIS quick look reduction package, use the task ilistdark to get a list of the exposure times of all your LIRIS science frames:
    in> ilistdark r*.fit
  • Put blanks into the light path:
    SYS> lblanks
  • Take the darks of the exposure times listed by ilistdark using dark:
    SYS> dark liris 10 "dark 10s"
    This takes one dark frame of 10s exposure time and the title of the FITS image is set to "dark 10s". You can write a script to get the dark frames for the exposure lengths needed and then execute it from the command line.

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