The 10-meter (34-foot) optical reflector at the Whipple Observatory was built in 1968 to pursue studies in gamma-ray astronomy; it has been in almost continuous nightly use since that time. The technique developed at the Whipple Observatory is the most sensitive method of detecting very-high-energy gamma-rays. It is an important complement to the studies from space using the CGRO.

The first galactic source of very-high-energy gamma-rays, the Crab Nebula supernova remnant, was detected by the Whipple group in 1989. The first extragalactic source, the active galaxy Markarian 421, was detected by the same group in 1992. There are now more than one dozen known cosmic sources of very-high-energy gamma-rays.

The Whipple Gamma-Ray Collaboration includes the Smithsonian Astrophysical Observatory, Iowa State University, Purdue University, Washington University, Leeds University (UK), and the National University of Ireland. Major funding support has come from the U.S. Department of Energy. More than 20 students have completed their doctoral dissertations on work done at this facility since 1982.

Although there are now more than ten major gamma-ray observatories around the globe, the Whipple telescope is still the largest and most sensitive gamma-ray telescope. However, major new observatories that will surpass the sensitivity of the Whipple telescope are now under construction in Spain , Australia, and Namibia (Africa) by international collaborations.