The Fred Lawrence Whipple Observatory is located on Mount Hopkins in Amado, Arizona, about 35 miles south of Tucson. Boasting dark skies, a dry climate, and good "optical seeing," it is the largest field station of the Smithsonian Astrophysical Observatory (SAO) and hosts a number of active telescopes. The 1.5m Tillinghast spectroscopic telescope once utilized the Z-machine (on display in this gallery), and is now used to find planets around other stars.
Whipple Observatory houses the MMT Observatory, a joint venture of the Smithsonian Institution and the University of Arizona. In 2000, the Observatory was upgraded with a 6.5-meter telescope that uses "adaptive optics" to remove the blurring effect of the atmosphere.
In 2007, an expansive observatory was completed at Whipple, in conjunction with a large consortium of institutions. It is called "VERITAS", or the Very Energetic Radiation Imaging Telescope Array System. Astronomers use VERITAS to study objects very far from Earth that emit the most energetic form of light known, called gamma rays.
Gamma rays from space are typically blocked by the Earth's atmosphere, and thus for many years, astronomers could not make ground-based observations of them. However, in 1938 the Russian physicist Pavel Cherenkov discovered that when a particle traveling at or near the speed of light in one medium travels into another medium where the speed of light is slower, the particle sheds an ephemeral blue flash of light. This is much like how a sonic boom is created when a jet has gone faster than the speed of sound in its medium.
A couple of decades later, British scientists applied Cherenkov's discovery to gamma rays traveling at the speed of light through space and striking Earth's atmosphere, where the speed of light is slower. Collaborations around the world were then made to create the first telescope (the Whipple 10-meter telescope, built at Whipple in 1968) that could observe this blue flash of light efficiently and reliably. The telescope uses a very large receiving area (a segmented mirror) with the ability to condense the faint flashes of light into a signal that could be measured.
VERITAS is an enhanced design of the Whipple telescope. The advanced system utilizes an array of four 12-meter optical reflector telescopes, one of which has been in operation since February 2005, and a telescope imaging system. With VERITAS, astronomers can boost the search for objects like supernova remnants, the left-overs of stars that have exploded, and active galactic nuclei, the center of galaxies that incur activity other than that of stars, and understand them with greater clarity.
VERITAS is a collaboration of groups from the United States, United Kindgom, Ireland, and Canada.