November 2013: At the recent "Trevorfest", a number of talks about the early development of VHE gamma-ray astronomy were presented. See them here.


A brief timeline of the development of ground-based gamma-ray astronomy through the Whipple and VERITAS projects:

  • 1953       Jelly and Galbraith: Cherenkov emission from atmospheric showers of charged particles is discovered.

  • 1958       Morrison publishes "On Gamma-ray Astronomy"

  • 1958       Chudakov and Nesterova: Development of the first large-scale instrument for TeV Gamma-ray astronomy, in the Crimea.

  • 1961       Hill and Porter: Successful imaging of Cherenkov light from a 1015 eV hadronic shower, using an image-intensifier with phosphor storage.

  • 1963       Jelley and Porter: Publication of "Cherenkov Radiation from the night sky and its application to Gamma-ray Astronomy", suggesting the use of image shapes to select gamma rays   and initiating a decade of collaborative work, with facilities operated at Harwell (UK) and Glencullen (Ireland).

Cherenkov work at the base of Mt. Hopkins in 1967.

  • 1966-68   Fazio and Weekes: Installation of SAO's Whipple 10m telescope at Mt. Hopkins; first purpose-built large reflector for TeV Gamma-ray Astronomy

  • 1968-76  Upper limits reported on many prominent sources

  • 1976-82  Whipple/SAO gamma-ray program closed down; TeV Gamma-ray astronomy enters the "Dark Ages"'

  • 1977       Turver and Weekes: In "Gamma-Ray Astronomy from 10-100 GeV", suggest use of PMT camera to record images, laying the groundwork for image analysis for gamma-hadron separation.

  • 1978       Porter and Weekes: Upper limits on density of primordial black hole explosions reported (using optical searchlights as light collectors).

  • 1979       Weekes and Fegan: Evaluate the potential of the National Solar Thermal Test Facility (NSTTF) at Sandia National Laboratories, as an optical detector of Cherenkov radiation

  • 1980-82  Weekes, Fegan, and Porter: construct an imaging system for implementation on the 10m Whipple telescope

  • 1982       Whipple Collaboration formally constituted (Hawaii, Iowa State, SAO, U.C. Dublin, Durham)

  • 1984       Imaging camera (37 pixel) installed on Whipple telescope

  • 1985       "VERITAS concept" proposed in Space Station Workshop at LSU

  • 1985       'Image-enhanced' detection of TeV gamma rays from the Crab Nebula reported at the 19th ICRC meeting in San Diego

  • 1989       Publication of detection of first galactic source by Whipple: the Crab Nebula

  • 1992       Detection of first extragalactic source by Whipple: Markarian 421

  • 1996       Internal proposal for VERITAS construction presented to SAO

  • 1998       VERITAS approved by SAO

  • 2000       VERITAS Collaboration formed (Chicago, Iowa State, Kansas State, Leeds, Purdue,  SAO,  U.C. Dublin, UCLA, Washington U.)

  • 2002       VERITAS proposal presented to NSF and DOE

  • 2003       Four telescope version of VERITAS approved by DOE, NSF and SAO.

  • 2007       First Light with VERITAS; all design specifications met or exceeded

The FLWO with VERITAS in summer of 2009. Note the background mountains and compare them to the picture above !

  • 2009       Array reconfigured (by moving T1) to increase sensitivity

  • 2012       All telescope cameras upgraded with new high-quantum-efficiency phototubes


And here is a copy of the presentation by Trevor Weekes about the history of gamma-ray astronomy, given at the VERITAS First Light Ceremony in April 2007.