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LIRIS Service Observations

Up to 8 hours of LIRIS observing time can be allocated through the ING Service Programme

INCLUDED observing modes

Imaging, using all available filters
Imaging polarimetry, using all available filters
Spectroscopy, using all available long slits and grisms

EXCLUDED observing modes

Multi-object spectroscopy (MOS) 



 In service mode the following restrictions apply:
  • The detector read-out speed is set to slow for all observations
  • the data store mode will be set to DIFF, i.e. the pre-read will be subtracted automatically from each image
  • the data read-out mode will be set to single read-out (correlated double sampling) for imaging and four non-destructive read-outs for spectroscopy


Darks and Bias  Only a limited number of calibration images are taken in service mode. Dark exposures are NOT taken by default, due to changes of the corresponding instrument characteristics during the night. If you require dark exposures, they must be taken immediately before or after your observations at night time, and thus have to be included in the total time requested. The use of bias frames is rather limited for the same reasons, and they are not provided unless specifically asked for.

Spectroscopic Flats  and Arcs and Imaging Sky Flats or Dome Flats will be taken automatically at the beginning or the end of the night and do not have to be requested.


Since the near-IR sky changes rapidly, observations of standard stars will not be taken unless explicitly asked for in the proposal and accounted for in the total time requested (photometry can often be done by means of 2MASS). If you request standard star observations of any type (photometric, spectrophotometric, telluric), then please explicitly state:

  • which specific standard star (give RA, DEC) you want for each object
  • which instrumental configuration you want: filters, slits and grisms.

Applications are often very nonspecific concerning standard stars, or unaware of the need for particular standards (various spectral types, for example, depending on the main target), or unaware of the fact that certain standard types do not exist in the vicinity of their targets. Thus, any standards required must be defined in the proposal by the applicant.

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Contact:  (LIRIS Instrument Specialist)
Last modified: 02 July 2019