Project Description


Whole Earth Blazar Telescope (WEBT)


The WEBT is an international consortium of astronomers observing blazars, i.e. active galactic nuclei with extreme variability properties.
The network includes telescopes that take data at the optical, near-infrared, and radio wavelengths.
The distribution in longitude of the telescopes allows us to obtain an almost continuous monitoring of the target sources, which enables a deep study of their variability properties and of the physical mechanisms producing it.
WEBT members also carry on polarimetric and sometimes spectroscopic observations.
The WEBT observing campaigns often involve observations at high energies, made possible by satellites that take data in the ultraviolet and X-ray bands (XMM-Newton, Swift) and in the gamma-ray band (AGILE, Fermi), or by ground-based Cherenkov telescopes (MAGIC).


The WEBT President and one of its Officers are astronomers working at OATo.
The President decides which campaigns to start, monitors their progress, takes part in the data analysis and interpretation, guarantees the data pubblication and archiving.
The Officer works in synergy with the President, leading observing campaigns, carrying out the data analysis and interpretation, and writing the papers to be published in international refereed journals.


The WEBT was born in 1997; since 2000 its leadership is at the OATo.
The international participation has been and is still very high (more than a hundred telescopes involved over the world), so WEBT activities are not expected to end in the near future.
Year after year collaborations with teams working with other facilities (in particular: AGILE, Fermi, MAGIC) have strengthened and new agreements with teams involved in future facilities (CTA) are developing.


Massimo Villata Email: massimo.villata at
Claudia M. Raiteri  Email: claudia.raiteri at