Brief Instruction on How to Observe

There is brief instructions on how to observe with TRISPEC. For more detailed instructions, please see each section about operating. Please note that the details given below are subject to change at any time.

  1. Running up the operating progarms


  2. Log in our computer "triview" using the account trispec. and open a image display and xterm windows from the computers "demi", and "trispec". And, start the operating programs on demi and on trispec. The specific instructions at UKIRT are here.
     
  3. Setting up the observation mode


  4. Type the following commands for each mode. For detail instruction on how to change observation mode, please see also here, and for the description about changing slit or filter, see also here. For polarimetry, in addition, half-wave retarder (for linear polarimetry) or quarter-wave retarder (for circular polarimetry) must be installed by the telescope operater or TSS.
     
  5. Target acquisition


  6. Let know the telescope operator or TSS, move the telescope to your target. After he or she set up a guide star, he or she will let know you that your target is ready. For adjusting the position of your target on the imaging detectors, you are able to offset the telescope via the instrument. At UKIRT, the toffset command is availble on demi for this (the detail imformation about operating the telescope via the insrument is here). About centering your target on the slit, see below.
     
  7. Centering on the slit (for spectroscopic modes only)


  8. Take image with the slit viewer using the rt.pl command, and offset the telescope so that your target into the middle of the slit. At UKIRT, the toffset command is avaiable on demi.

    For peaking up for the faint target (specially in optical) should be arrive with very accurate offsets from a nearby bright star. Or, after adjusting the position of target on the imaging mode, change to spectroscopic mode again.
     

  9. Taking data


  10. At first, for determining the suitable exposure time for each channel, take test exposure using the read.pl command without prefix. After checking if these don't saturate on all channels, take data using  read.pl command with prefix related to target name. For example, type "read.pl 3 4 5 ngc7027" on demi.

    For linear polarimetry, it is useful to use the linpol.sh script instead of the read.pl command. The linpol.sh script will take frames with rotating half-wave plate to 0, 45, 22.5, 67.5 degrees in sequence. For example, type "linpol.sh 3 4 5 ngc7027" on demi.

    For circular polarimetry, it is useful to use the cirpol.sh script instead of the read.pl command. The cirpol.sh script will take frames with rotating quarter-wave plate to 0, 90, 45, 135 degrees in sequence. For example, type "cirpol.sh 3 4 5 ngc7027" on demi.

  11. Taking arc frame (for spectroscopic modes only)


  12. For obtaining wavelength calibration data, take arc frame using the arc.sh command. For example, type "arc.sh 0.302 4 5 hg_ar_0" on demi, then three arc images with the prefix "hg_ar_0" with exposure times of 0.302, 4, and 5 seconds for each channel will be created. Since slight shifts in the calibration are possible when you change mode, slits, and grisms, and when the attitude of the instrument change largely, you should take arc frame after that.
     
  13. Taking flat frame


  14. For obtaining flatfield frame on the imaging modes, you should take night sky images (for only the infrared channels), or twilight sky images (for all channels). For the spectroscopic modes, take dome flats. At UKIRT, the TSS will prepare the Tungsten-Halogen lamp for dome flats.
     
  15. Running down the operating programs


  16. Terminate the operating programs on demi and on trispec, and log out from trivew. The specific instructions at UKIRT are here.

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Last Modification Date: 2001/02/20
Last Modification Author: Makoto Watanabe <watanabe@z.phys.nagoya-u.ac.jp>