An open association of Institutes and Laboratories willing to collaborate in the exploitation and development of long baseline interferometry.

The European Interferometry Initiative (Eii) is an open association of Institutes and Laboratories willing to collaborate in the exploitation and development of optical long baseline interferometry in optical/infrared astronomy. The Eii confederates the activities included in the European Commission instruments of the 6th, 7th and H2020 R&D program, including the most recent Optical/RadioNet Pilot Program. The current Eii activities are:

  • The establishment of a network of VLTI expertise centres across Europe
  • A joint research activity preparing for the third generation of VLTI instruments
  • The Fizeau staff exchange programme
  • The organisation of VLTI training summer schools and VLTI open days

Funding for the activities was obtained through the OPTICON/RadioNet Pilot Program (2021-2024; grant agreement 101004719), OPTICON - the Optical Infrared Co-ordination Network for astronomy - Horizon 2020 (2017-2020, grant agreement 730890), OPTICON FP7 II (2013-2016, grant agreement 312430), OPTICON FP7 (2009-2012, grant agreement 226604), ONTHEFRINGE (2006-2008: grant MSCF-CT-2005-029954) and OPTICON FP6 (2002-2006, RII3-Ct-2004-001566).

The MoU and Management composition can be found here.


This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 101004719. This material reflects only the authors views and the Commission is not liable for any use that may be made of the information contained therein.



OPTICON/RadioNet Pilot Program

Under H2020-INFRAIA-2018-2020, the European Commission approved the new project OPTICON/RadioNet Pilot (ORP), which mobilizes the two flagship communities of advanced radio and optical/infrared astronomy.

2024B Transnational Access Call

We are pleased to announce that the 2024B transnational access call for observing time at optical/IR telescopes supported by the OPTICON-Radionet Pilot (ORP) project is now open. The call will close 11th March 2024 at 23.59 UT.

12th VLTI Summer School

The 12th VLTI Interferometry School will be held on the week before (online) and on 22-28 September 2023 in Porquerolles, Provence, France.

ORP Milti-Facility Call for Proposals

The call for proposals is aimed at observing programmes that require multiple astronomical observing facilities to deliver unique scientific programmes. Deadline for submission: 9 April 2024 - at 14:00 UTC/ 15:00 BST/16:00 CEST.