The 4m International Liquid Mirror Telescope Project

sponsored by

University of Liège Le Fonds de la Recherche Scientifique  Région Wallonne Natural Sciences and Engineering Research Council of Canada Royal Observatory of Belgium Aryabhatta Research Institute of Observational-Sciences (ARIES), Nainital  University of Poznan, Poland

The International Liquid Mirror Telescope (ILMT)

is a 4m class telescope project, in which several institutions from different countries are actively involved.

The ILMT uses Liquid Mirror technology : the primary mirror of the telescope is a rotating container with highly-reflecting liquid in it (mercury). The surface of the spinning liquid takes the shape of a paraboloid.

The ILMT is a promising instrument which can be entirely dedicated to a specific scientific project. Indeed, its low cost makes it a unique survey instrument. As liquid mirror telescopes cannot be tilted, they cannot track like conventional telescopes do. The tracking is done artificially by using a technique called time delayed integration (TDI), which uses a CCD detector that tracks by electronically stepping its pixels. The ILMT will be equipped, at its prime focus, with a time-delay-integration (TDI) corrector capable of imaging a field of 30x30 arcminutes with a resolution better than one arcsecond. The ILMT will carry out direct imagery using a 4K x 4K thinned CCD as the detector working in the TDI mode.

It will be installed at Devasthal (India) where it will monitor a strip of sky of 0.5 degree of declination down to a limiting magnitude of about 23 in the I band in a single integration. This survey will last for about five years. The information will be stored on disks so that the night observations can be coadded with a computer to lead to long equivalent integration times.

Team members

  • List of the team members and contact information


  • Latests news and headways on the ILMT projects
  • ILMT project History


  • Basics on Liquid Mirror Telescope technology
  • Description of the ILMT components and their present status


Description of the scientific goals of the ILMT project:
  • quasar and gravitational lenses
  • supernovae detection



Extragalactic Astrophysics and
Space Observations
Institut d'Astrophysique et de Géophysique, Liège University, Allée du 6 Août, 17 (Sart Tilman, Bât. B5c), 4000 Liège, Belgique Tel.: 04.366.97.55, Fax: 04.366.97.46
©fata morgana