La Silla Paranal Observatory News

The page contains important news and events of the La Silla Paranal Observatory. It also covers some important telescope and instruments news from the La Silla, Paranal and APEX sites.

General News

Paranal News

Telescope News


  • UT3
    • January: SINFONI installed on cassegrain focus
  • UT4
    • January: the telescope loses SINFONI waiting for the NEAR experiment


  • UT3
    • December: VISIR moved from cassegrain focus to NIH for NEAR upgrades
  • UT4
    • May: Altitude motor repair
    • March/April: DSM binary chopping test


  • All UTs
    •  November: TCS VLT2017 upgrade
  • UT2
    • May: Enclosure Rotation drives upgrade
  • UT3
    • December: Enclosure PLC upgrade
    • October: Altitude Drives upgrade
    • May/June: Espresso Coudé train installation
    • April: M1/M3 recoating
  • UT4
    • November-December: LGSF maintenance and LPC swap
    • October-December: GRAAL comissioning runs
    • May-September: GALACSI WFM commissioning
    • August: M1/M3 re-coating
    • May: Altitude Drives Upgrade
    • April
      • realignment of Nasmyth B assembly of Adapter/Rotator, its support structure and GALACSI. 5 tons of equipment and steel moved of ~1.5 mm without dismounting from the telescope fork structure (TTR 99.0045)
      • completion of first phase of AOF-GALACSI commissioning
    • March: UT4 Naysmith B Drive Motor: removal of magnet protection plates and out-of-service cooling lines
    • February
      • UT4 altitude motor segment replacement (TTR-098.0077)
      • completion of first phase of AOF-GRAAL commissioning


  • UT2
    • 7-12 December: M1/M3 recoating
  • UT4
    • 2 December: return to Science operations after DSm integration
    • 24 October: first light with DSM after its integration


  • 20th November: recoating of M1, M3 of UT2 completed
  • 11th September: recoating of M1, M3 of UT4 completed
  • 1st April: The VST is currently out of service between March 29, 2013, and April 2, 2013 due to a multiple damage of cables and cooling lines after an incident caused by the failure of a limit switch. All damaged parts were replaced or repaired.
  • 26th February: The Laser Guide Star system at UT4 has recently been successfully upgraded with a fibre Raman laser (AOF prototype) delivering improved on-sky performances as well as enhanced operational stability and maintenance. Full characterization of the upgraded system will soon be available. This intervention will result in a dramatic increased in the availability of the LGS system for science operations.


Instrument News


  • June 25th: SINFONI has been warmed up for its decommissioning. SPIFFI will come back next year after upgrade and integration within ERIS.
  • May: KMOS: During an intervention, arms #4 and 8 have been replaced. However, arm#14 showed a hard point and was left in simulation in park position.
  • May 7-12: X-shooter is unavailable due to a Cassegrain intervention.
  • April 19: KMOS arm #8 is stuck and deployed in the field-of-view at its maximum linear extent.  


  • November 27 to December 7: X-shooter is not available due to maintenance.
  • September 23: An earth tremor caused a shift in the direction perpendicular to the dispersion direction of ~4 pixels in the HR grating only.  An intervention on 13-Oct-2018 returned the grating to its original position.
  • October 1: All observations should now be prepared with p2; visiting astronomers in the control room can also use vOT. See
  • October 1: FORS2: the high time resolution modes (imaging, HIT-I; spectroscopy, HIT-S; and multi-object spectroscopy, HIT-MS) are no longer offered.
  • October 1: KMOS arm #4 has started to fail in all its movements since September 26; it was placed in simulation.
  • August: KMOS: Failure of a cold head leads to an emergency intervention to replace it. Following the intervention, the performances of spectrograph #2 are degraded with astigmatism along the spatial direction  and spectral direction with and degraded resolution of ~10%.
  • July: NACO: Due to unrecoverable problems, the visible wavefront sensor was decommissioned.
  • May: KMOS intervention to maintain the cold heads and fix/replace the underperforming arms (namely arm #1, #3 and #17). Arm 1 and 3 have been replaced and arm 17 fixed
  • April 12 - May 24th: NACO: polarimetry has not been available  due to an issue with the retarder.
  • March: NACO had several issues with the CONICA detector.
  • Janury 7: KMOS arm #17 also shows a rotator-angle dependent flux loss since December 2018.


  • November 14: KMOS arm #1 shows flux loss of up to 40%. In addition, the flux loss depends on the rotator angle.
  • October: UVES: Second and final part of the intervention on the blue camera lenses, to recover the resolution of the UVES blue arm, is now completed. The resolving power in the UVES blue arm is back to its early-days values, with a most-recent median measurement of R~93,000 (for the 0.4-arcsec slit).
  • April: NACO: the CONICA detector is very unstable.
  • February: UVES: An intervention to improve the resolution of the blue arm, which has shown to degrade slowly through the years due to aging of the blue camera, took place. The resolving power measured after the intervention is ~85,000 for the 0.4-arcsec slit. The RMS of the residuals of the wavelength calibration improved by a factor of two.
  • January 9: KMOS: Arm 3 is still in simulation and will remain in this state as soon as the instrument can be warmed up and the arm fixed/replaced. Even though the astrometry is indeed re-calibrated, Arm 3 is still showing vignetting on sky with such vignetting being dependent on the arm and rotator position.


  • December 20: X-shooter: After X-shooter was remounted following the last mirror recoating, the readout noise is much higher in the VIS arm. All observations since 2016-12-20 are affected. The readout noise increased by 20-70% depending on the readout mode used, see Unfortunately, the cause has not yet been identified.
  • December 19: UT4 instruments. Following the installation of the deformable secondary mirror, all instruments on UT4 have now been recommissioned and are back in operation.
  • December 5: NACO: The first part of an effort to re-align NACO has been completed. The field stop was re-aligned and the number of AO modes significantly reduced. Performance using the VIS wavefront sensort is nominal; additional work will be done in January 2017 for the IR WFS.
  • November 25: VIMOS: The IFU intervention was completed and we have been observing different specphots to adjust the center of the IFU. The pointing accuracy is now within operational limits given the blind IFU pointing (3 arcsec).
  • November 12: VIMOS: The IFU unit is currently inoperative due to a problem with the IFU shutter. An intervention will take place shortly, most likely before Nov 17.
  • October 9: All UT4 instruments are unavailable due to the installation of the Deformable Secondary Mirrors. Operation will restart in December.
  • October 1: GRAVITY enters operation with the auxiliary telescope array in spectro-imaging mode for the medium and high spectral resolution settings. Gravity can be used in both single and dual field modes (i.e. both on-axis and off-axis fringe-tracking).
  • September 13: SINFONI: The MACAO shutter for the AO unit was replaced successfully.
  • September 5: KMOS: Arm 3 is experiencing again issues: bad precision in positioning as before plus vignetting. These issues are under investigation and Arm 3 is set to simulation.
  • July 11: FLAMES: A new version of FPOSS is available.
  • July 8: KMOS: arm #3 shows problems. It had been set to simulation for a short period (25th July to 4th August)  but is now working again, albeit with a higher uncertainty on the positioning (about 3 pixels). For that reason, the arm to take the telluric standard for spectrograph 1, was changed from #3 to #4.
  • May 18-22: OmegaCAM was out of operations for maintenance.
  • April 2: UVES: An intervention to restore the full performance of the blue arm took place at the period change over to P97. The blue-arm camera is now back to its condition pre-earthquake, i.e., the blue arm delivers a resolving power of ~75,000 for a slit width of 0.4 arcsec.
  • March 31: SINFONI has been upgraded. See the News page for further information.
  • Feburary 27: A new Giraffe readout mode will be availble in Visitor Mode only from Period 97. The mode is a high gain, low noise, slow readout mode that results in higher S/N (about a factor 2) only for faint targets, i.e. at the limit of the instrument sensitivity. The readout time of this slow mode is about 180s, whereas in the standard readout mode this is 45s. The ETC already includes the new readout mode in the Instrument Setup section. More details will be available in the User and Template manuals.
  • February 21: The PSF was fully recovered on February 18th. Image quality and contrat performances are now back to nominal.
  • Feburary 5: VIRCAM: The response in the upper half of chip #16 has decreased after the intervention in Nov 2015. The effect is more pronounced in the Z band, and to a lesser extent in Y, J and the narrowband filters. Before the intervention, the fractional response in the upper half was ~50%-70% in Z. After the intervention it has decreased to ~40%. This issue is under investigation.
  • February 4: SPHERE:  Since January 19th, SPHERE suffers from a degraded image quality (a factor ~0.9 to the H-band Strehl ratio and a factor ~0.5 to the R-band Strehl ratio). The PSF core has a "cross" like shape". The team is working on finding as solution. SPHERE is kept in operations.


La Silla News

The section provides the latest telescope and instruments news from the La Silla Site.

More news can be found in the news section of theLa Silla Science Operations page.

  • March 14, 2010: Updated service observing information Service Observing
  • November 20, 2009: A new technique using near-infrared images, obtained with s 3.58-metre New Technology Telescope (NTT)ESO Watching a Cannibal Galaxy Dine
  • April 6, 2009: La Silla Astroclimatology information (weather, seeing, extinction) was moved to a new location and can now be found on the mean navigation menu of the La Silla Facilities pages. Additional La Silla astroclimatology information will be added here.
  • February 11, 2009: From the second week of July, 2009, observations will be carried out from a new control room located in theadministration building.
  • February 11, 2009: A new page describing the way that operations will run after P83 (ie from October 2009) is available here.
  • April 22, 2008: A document that explains how to interface visitor instruments with focal stations of La Silla telescopes is available (2.8 MB PDF format).
  • March 27, 2007: The dome of the 3.6m has been fully restored, and moves with nominal speed.
  • October 05, 2006: The dome of the 3.6m enters an extended period of corrective maintenance. Science operations at the 3.6m is temporarily suspended until further notice.
  • May 17, 2006: A Trio of Neptunes  discovered with HARPS, see ESO PR 18/06
  • January 26, 2006: A 5.5M_earth planet discovered with the 1.54m Danish telescope.