The Very Large Telescope in 2030 – a key conference for Australia

By Mike Ireland 
[email protected]

Between June 17 and 21 this year, an exciting, rare and strategic meeting will take place in Garching on The VLT in 2030. The existing complement of VLT/I instrumentation was largely defined a decade or more ago, with no new instruments approved in the past 5 years. The long term future of the observatory is uncertain, with a range of possible changes to instrumentation and operations.
These could include:

  • More emphasis on surveys and large programs once the ELT is constructed.
  • A smaller complement of instruments, leaving room for visitor instruments.
  • Instrument upgrades instead of new instruments, in order to not lose the capability of existing (ageing) instruments.
  • Adding laser guide stars to all telescopes, enabling interferometry of much fainter stars on the UTs.
  • Significantly modifying a UT so that the UTs can no longer be used for interferometry.
  • Discussion of a conventional major new UT instrument, such as Blue-MUSE.
  • High contrast interferometry with the VLTI, bringing extreme AO to finer spatial scales.

This meeting is likely to be the only opportunity for broad community input into the future of VLT/I during the current term of Australia’s strategic partnership with ESO. In order to summarise the current situation, here is some key background information:
Scientific Context
A significant part of this conference will be devoted to defining the scientific context of Paranal. Although split into scientific areas, this will be in the context of answerable questions with other facilities. Time domain astronomy is expected to substantially grow with LSST,  the rich data sets from space survey instruments (e.g. Gaia, WFIRST, PLATO) will significantly change the focus of many observational astronomers, and the premier follow-up instruments are likely to be the ELT and JWST.
Known Instrument Changes
 The following known changes to Paranal will occur well before the era being discussed at this meeting.

  • Once MOONS and 4MOST are in operation, FLAMES will likely be decommissioned.
  • SINFONI and NACO are to be replaced with ERIS.
  • If MAVIS is approved and moves to the construction phase, it will replace HAWK-I.

Ageing Instrumentation
Towards the end of the next decade, instruments more than 15 years old are not expected to keep operating without upgrades. This includes FORS2 (already part of upgrade plans now), UVES, KMOS and X-SHOOTER, plus PIONIER on the VLTI.
Obsolete Instrumentation
In the ERA of JWST and ELT, some Paranal instrumentation will arguably become obsolete for many science cases. This will include: 

  • KMOS, largely superseded with JWST-NIRSpec and ELT-HARMONI IFU and multi-object spectroscopy due to the greatly improved sensitivity.
  • VISIR, largely superseded with JWST-MIRI.
  • SPHERE’s infrared imaging science will largely be superseded by JWST imaging. Without a major upgrade and rebuild (replacing the Shack-Hartmann sensor), it will no longer be competitive.

Under the assumption that these instruments are decommissioned without additional funds, this would leave 4 empty instrument slots on the UTs.
New Instruments
In the current Paranal Instrumentation Plan, there are 2-4 new instruments or significant upgrades (in addition to MAVIS) to be delivered before 2030, with an anticipated timescale of 8 years for a new instrument between a call for Phase A studies and Preliminary Acceptance Chile.  In the existing Paranal Instrumentation Plan, a Cassegrain UV spectrograph, a UVES upgrade and a SPHERE upgrade all have some clear justification. This would leave room for only ~1 new instrument in the Paranal budget (on VLT or VLTI), plus 2 visitor instrument slots each on the VLT and VLTI. Are Australian astronomers content with this status quo? Leave us your comments below.


Michael Murphy is the Australian representative on the ESO Science Technical Committee. Contact: [email protected]

Sarah Sweet is the Australian representative on the ESO Users Committee. Contact: [email protected]

Stuart Ryder is a Program Manager with AAL. Contact: [email protected]

Guest posts are also welcome – please submit these to [email protected]