Important recent changes (since Periods 90 and 91) regarding La Silla, Paranal and APEX instrumentation and facilities

La Silla


As part of the agreement between ESO and the Max Planck Gesellschaft, the 2.2m is NOT offered to use by the ESO community during Period 92.


UT instruments and facilities

    • depending on the approval of a major upgrade project, the instrument will be taken out of operations for one year starting possibly in the second semester of 2014. Therefore Large Programmes using CRIRES will not be accepted;
    • calibration frequency may decrease during P92.
  • FORS2: Since P91, a new functionality has been added to the fast acquisition templates (including the RRM ones) for long-slit spectroscopy, spectropolarimetry, and spectrophotometry. It is now possible to align the slit along any direction defined by two objects and use several centering options.
  • KMOS is expected to enter in operations early in Period 92.
  • FLAMES: The UVES fiber 37 on plate 2 is broken since Septembre 11, 2012. The latest attempt to fix it yielded 30% of the original transmission. Therefore the fiber will remain disabled until better results are reached or the fiber is replaced. Data obtained with the missing fiber can be reduced with the patched version of the FLAMES/UVES pipeline. Users are invited to discuss with with their USD support astronomer during phase 2 preparation to devise a strategy to cope with the missing fiber.
  • A Visitor Focus is offered for visitor instrument at the Cassegrain focus of UT2 during Period 92.
    • XSHOOTER is offered on UT3 in P92.
    • Telluric standard stars are observed in nodding instead of staring mode since Period 91. The 400 kHz readout mode for the UVB/VIS arms will be used independently of the readout speed used for the science observations. Detector binning will be the same as for the science observations. This change gives a better correction of the telluric emission and absorption lines as well as bad pixels, especially in the NIR arm. The provided S/N will be between 50-150 by default. Users requiring higher S/N are encouraged to submit their own telluric star OBs, in which case the corresponding execution time must be included in the time requested at Phase 1. There is no change for the IFU telluric standard stars observations.
    • The Atmospheric Dispersion Correction (ADC) systems on the UVB/VIS arms are not reliable. Since August 1st, 2012, the ADCs have been fixed in their non-deviation position. Data obtained in this configuration can be reduced by the pipeline without significant degradation. Updates on the status of the ADCs can be found on the XSHOOTER news webpage. The latest version of the user manual provides plots for helping users prepare observations without ADCs.
      Users are recommended to carry out observations at the parallactic angle whenever possible or to take special care on the airmass constraint to avoid flux loss.
  • ISAAC is offered again during the first part of Period 92, due to the delayed arrival of SPHERE. The RA range of targets starts at 22h. ISAAC will be decommissioned approximatively 2 months before the arrival of SPHERE.
  • SPHERE is expected to enter integration and commissioning during Period 92.
  • VIMOS:
    • A review of the current policy of calibrating all the MOS modes at night will take place during P90 and P91. The expected outcome is that all MOS modes can be calibrated during the day, with the possible exception of the HR_blue mode. All IFU modes will continue to be calibrated during the night.
    • A refurbishment of the Grism Exchange Unit may take place during P92 to improve its reliability.
    • No Large Programmes are accepted for VIMOS due to a significant number of existing commitments.
  • VISIR underwent a major intervention during P89. However, as the properties of its new detectors are not within specifications, it has been taken out of operations for P91 and is not offered in P92.
  • As of February 2013, PARLA, a prototype of the laser used by the coming Adaptive Optics Facility (see the AOF booklet in pdf format), replaces PARSEC within the Laser Guide Star Facility (LGSF). Thanks to the increase in delivered power and large improvement in reliability, the number of nights during which the LGSF can be used every month will be signicantly increased. However, taking into account the existing commitments for this facility (in particular, for ongoing Large Programmes and for Guaranteed Time Observations), it is expected that only a limited amount of time can be allocated in Period 92 to new programmes requiring the use of the LGSF. Accordingly, proposers are encouraged to carry out a critical assessment of the need for LGS for execution of their observations, and to carefully study the possibility of using a Natural Guide Star (NGS).
  • NACO:
    • NACO is offered in Period 92 until approximately 2 months before the arrival of MUSE, after which NACO will be removed from the UT4 Nasmyth B platform.
    • The annular groove phase mask (AGPM) "vortex" coronagraph is offered in both SM and VM. It is optimized for the L' band (L_prime, NB_3.74 or NB_4.05 filter). Associated to pupil tracking, it can provide an inner working angle down to ~0.1" and an outer working angle up to ~7".
  • MUSE is expected to enter integration and commissioning during Period 92.
  • No Large Programmes will be accepted on any UT4 instruments.


  • MIDI:
    • is expected to be decommissioned during Period 93, therefore no Large Programmes will be accepted for this instrument.
    • Since Period 91 MIDI can be operated with the FSU-A as an external, on-axis fringe-tracker. FSU-A works in K-band. When the science data are reduced using the fringe tracker data, MIDI+FSU-A with the ATs is able to attain a sensitivity for correlated fluxes similar to what used to be possible with the UTs. Because of the UT vibrations, however, the FSU-A offers no sensitivity advantage for the UTs, i.e. the limiting magnitude in the K-band for fringe recording is the same for the UTs as for the ATs. Observations with MIDI/FSU-A and the UTs can only be considered if a benefit over using the ATs is convincingly demonstrated (e.g. off-axis AO guide star availability). MIDI+FSU-A is only offered in the correlated flux mode.
      This configuration is only offered in visitor mode.
      Since ESO does not provide a reduction pipeline for the correlated flux mode obtained with FSU-A, it is only recommended for users with expertise in reducing correlated flux mode data.
  • AMBER: Thanks to a recent intervention on the cryogenic spectrograph, the instrument has gained 1 and 0.5 magnitude in sensitivity in H and K band, respectively, in all spectroscopic modes. See the updated table of the limiting magnitudes as function of atmospheric conditions and observing modes.
  • No Large Programme for VLTI Visitor instruments will be accepted in Period 92.




  • Zspec: this broadband spectrograph is no longer offered at APEX.