From UC Santa Cruz: “Scientists to inaugurate a new type of gamma ray telescope at Whipple Observatory”

UC Santa Cruz

From UC Santa Cruz

January 16, 2019
Tim Stephens

The prototype Schwarzschild-Couder Telescope (pSCT) is a novel type of gamma-ray telescope designed for the Cherenkov Telescope Array (CTA). (Photo by Amy Oliver, Fred Lawrence Whipple Observatory, Center for Astrophysics, Harvard & Smithsonian)

A new type of gamma-ray telescope will be unveiled January 17 in an inauguration event at the Fred Lawrence Whipple Observatory in Amado, Arizona. Expected to see first light in early 2019, the telescope is a prototype Schwarzschild-Couder Telescope (pSCT) designed for the Cherenkov Telescope Array (CTA), the next generation ground-based observatory for gamma-ray astronomy at very high energies.

David Williams, adjunct professor of physics at UC Santa Cruz, chairs the CTA-US Consortium.

“The inauguration of the pSCT is an exciting moment for the institutions involved in its development and construction,” Williams said. “The first of its kind in the history of gamma-ray telescopes, the SCT design is expected to boost CTA performance towards the theoretical limit of the technology.”

The CTA Observatory, for which construction will begin in 2019, will be the world’s largest and most sensitive high-energy gamma-ray observatory, with more than 100 telescopes located in the northern and southern hemispheres.

The 9.7-meter aperture pSCT is a pathfinder telescope for use in the CTA and exploits a novel optical design. Its complex dual-mirror optical system improves on the single-mirror designs traditionally used in gamma-ray telescopes by dramatically enhancing the optical quality of their focused light over a large region of the sky, and by enabling the use of compact, highly-efficient photo-sensors in the telescope camera.

“Ultimately, the SCT is designed to improve CTA’s ability to detect very-high-energy gamma-ray sources, which may also be sources of neutrinos and gravitational waves,” said Vladimir Vassiliev, principal investigator of the pSCT. “Once the SCT technology is demonstrated at FLWO, it is hoped that SCTs will become a part of at least one of the two CTA arrays, located in each of the northern and southern hemispheres.”

The CTA Observatory (CTAO) will consist of 118 telescopes of three different sizes and is expected to detect sources of gamma rays in the energy range 20 GeV to 300 TeV, with about ten times increased sensitivity compared to any current observatory. Notable for providing improved gamma-ray angular resolution and its very-high-resolution camera (more than 11,000 pixels), the SCT is proposed for the medium-sized CTA telescopes and will primarily contribute to the middle of CTA’s energy range (80 GeV to 50 TeV).

“The SCT and other telescopes at CTA will greatly improve upon current gamma-ray research being conducted at HAWC, HESS, MAGIC, and VERITAS, the last of which is located at the Fred Lawrence Whipple Observatory,” said VERITAS Director Wystan Benbow.

HAWC High Altitude Cherenkov Experiment, located on the flanks of the Sierra Negra volcano in the Mexican state of Puebla at an altitude of 4100 meters(13,500ft), at WikiMiniAtlas 18°59′41″N 97°18′30.6″W. searches for cosmic rays

HESS Cherenkov Telescope Array, located on the Cranz family farm, Göllschau, in Namibia, near the Gamsberg searches for cosmic rays, altitude, 1,800 m (5,900 ft)

MAGIC Cherenkov telescopes at the Observatorio del Roque de los Muchachos (Garfia, La Palma, Spain))

CfA/VERITAS, a major ground-based gamma-ray observatory with an array of four 12m optical reflectors for gamma-ray astronomy in the GeV – TeV energy range. Located at Fred Lawrence Whipple Observatory,Mount Hopkins, Arizona, US in AZ, USA, Altitude 2,606 m (8,550 ft)

“Gamma-ray observatories like VERITAS have been operating for 12 to 16 years, and their many successes have brought very-high-energy gamma-ray astronomy into the mainstream, and have made many exciting discoveries. We hope CTA will supersede VERITAS around 2023, and it will be used to continue to build upon the 50 years of gamma-ray research at the Whipple Observatory and elsewhere.”

The Whipple Observatory is operated by the Harvard-Smithsonian Center for Astrophysics.

The SCT optical design was first conceptualized by U.S. members of CTA in 2006, and the construction of the pSCT was funded in 2012. Preparation of the pSCT site at the base of Mt. Hopkins in Amado, AZ, began in late 2014, and the steel structure was assembled on site in 2016. The installation of pSCT’s 9.7-meter primary mirror surface, consisting of 48 aspheric mirror panels, occurred in early 2018, and was followed by the camera installation in June 2018 and the 5.4-meter secondary mirror surface installation, consisting of 24 aspheric mirror panels, in August 2018.

Leading up to the inauguration and in preparation for first light, scientists opened the telescope’s optical surfaces in January 2019. The SCT is based on a 114-year-old dual-mirror optical system first proposed by Karl Schwarzschild in 1905. It became possible to construct only recently as a result of critical research and development progress made at both the Brera Astronomical Observatory and Media Lario Technologies Incorporated in Italy.

The pSCT was made possible by funding through the U.S. National Science Foundation Major Research Instrumentation program and by the contributions of thirty institutions and five critical industrial partners across the United States, Italy, Germany, Japan, and Mexico.

More information about the pSCT is available online at

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UCSC Lick Observatory, Mt Hamilton, in San Jose, California, Altitude 1,283 m (4,209 ft)


UCO Lick Shane Telescope
UCO Lick Shane Telescope interior
Shane Telescope at UCO Lick Observatory, UCSC

Lick Automated Planet Finder telescope, Mount Hamilton, CA, USA

Lick Automated Planet Finder telescope, Mount Hamilton, CA, USA

UC Santa Cruz campus
The University of California, Santa Cruz, opened in 1965 and grew, one college at a time, to its current (2008-09) enrollment of more than 16,000 students. Undergraduates pursue more than 60 majors supervised by divisional deans of humanities, physical & biological sciences, social sciences, and arts. Graduate students work toward graduate certificates, master’s degrees, or doctoral degrees in more than 30 academic fields under the supervision of the divisional and graduate deans. The dean of the Jack Baskin School of Engineering oversees the campus’s undergraduate and graduate engineering programs.

UCSC is the home base for the Lick Observatory.

Lick Observatory's Great Lick 91-centimeter (36-inch) telescope housed in the South (large) Dome of main building
Lick Observatory’s Great Lick 91-centimeter (36-inch) telescope housed in the South (large) Dome of main building

Search for extraterrestrial intelligence expands at Lick Observatory
New instrument scans the sky for pulses of infrared light
March 23, 2015
By Hilary Lebow
The NIROSETI instrument saw first light on the Nickel 1-meter Telescope at Lick Observatory on March 15, 2015. (Photo by Laurie Hatch) UCSC Lick Nickel telescope

Astronomers are expanding the search for extraterrestrial intelligence into a new realm with detectors tuned to infrared light at UC’s Lick Observatory. A new instrument, called NIROSETI, will soon scour the sky for messages from other worlds.

“Infrared light would be an excellent means of interstellar communication,” said Shelley Wright, an assistant professor of physics at UC San Diego who led the development of the new instrument while at the University of Toronto’s Dunlap Institute for Astronomy & Astrophysics.

Wright worked on an earlier SETI project at Lick Observatory as a UC Santa Cruz undergraduate, when she built an optical instrument designed by UC Berkeley researchers. The infrared project takes advantage of new technology not available for that first optical search.

Infrared light would be a good way for extraterrestrials to get our attention here on Earth, since pulses from a powerful infrared laser could outshine a star, if only for a billionth of a second. Interstellar gas and dust is almost transparent to near infrared, so these signals can be seen from great distances. It also takes less energy to send information using infrared signals than with visible light.

Frank Drake, professor emeritus of astronomy and astrophysics at UC Santa Cruz and director emeritus of the SETI Institute, said there are several additional advantages to a search in the infrared realm.

“The signals are so strong that we only need a small telescope to receive them. Smaller telescopes can offer more observational time, and that is good because we need to search many stars for a chance of success,” said Drake.

The only downside is that extraterrestrials would need to be transmitting their signals in our direction, Drake said, though he sees this as a positive side to that limitation. “If we get a signal from someone who’s aiming for us, it could mean there’s altruism in the universe. I like that idea. If they want to be friendly, that’s who we will find.”

Scientists have searched the skies for radio signals for more than 50 years and expanded their search into the optical realm more than a decade ago. The idea of searching in the infrared is not a new one, but instruments capable of capturing pulses of infrared light only recently became available.

“We had to wait,” Wright said. “I spent eight years waiting and watching as new technology emerged.”

Now that technology has caught up, the search will extend to stars thousands of light years away, rather than just hundreds. NIROSETI, or Near-Infrared Optical Search for Extraterrestrial Intelligence, could also uncover new information about the physical universe.

“This is the first time Earthlings have looked at the universe at infrared wavelengths with nanosecond time scales,” said Dan Werthimer, UC Berkeley SETI Project Director. “The instrument could discover new astrophysical phenomena, or perhaps answer the question of whether we are alone.”

NIROSETI will also gather more information than previous optical detectors by recording levels of light over time so that patterns can be analyzed for potential signs of other civilizations.

“Searching for intelligent life in the universe is both thrilling and somewhat unorthodox,” said Claire Max, director of UC Observatories and professor of astronomy and astrophysics at UC Santa Cruz. “Lick Observatory has already been the site of several previous SETI searches, so this is a very exciting addition to the current research taking place.”

NIROSETI will be fully operational by early summer and will scan the skies several times a week on the Nickel 1-meter telescope at Lick Observatory, located on Mt. Hamilton east of San Jose.

The NIROSETI team also includes Geoffrey Marcy and Andrew Siemion from UC Berkeley; Patrick Dorval, a Dunlap undergraduate, and Elliot Meyer, a Dunlap graduate student; and Richard Treffers of Starman Systems. Funding for the project comes from the generous support of Bill and Susan Bloomfield.