CACTUS
CACTUS began its life not as a telescope but as a power plant. Outside Daggett, California, near Barstow, a facility once known as Solar Two gathered sunlight in the desert. Then, starting in 2001, that power plant was converted into an observatory. The name it took was a mouthful: Converted Atmospheric Cherenkov Telescope Using Solar-2. How does a solar power station become a tool for studying the sky? And why, only a few years later, would it be torn down entirely? The answers run through a short and unusual stretch of desert science.
Solar Two was the starting point. The facility outside Daggett had been built to capture the sun's energy, and its hardware sat ready in the California desert. Beginning in 2001, that infrastructure was repurposed into a ground-based Air Cherenkov Telescope, the type of instrument abbreviated as ACT. The conversion turned a station designed to harvest sunlight into one designed to catch faint light from the cosmos. By the fall of 2004, the first astronomical observations had begun.
November 2005 marked the end of CACTUS as a working observatory. Its last observing runs took place that month, closing a stretch of active science that had opened barely a year earlier. The reason was money. Funds for observational operations from the National Science Foundation were no longer available, and without that support the telescope could not keep watching the sky. A facility converted over several years had only a short season of use.
The University of California, Davis ran the day-to-day operation of CACTUS, while the land and equipment belonged to Southern California Edison. That split between operator and owner placed a university research effort on infrastructure held by a utility company. After the observing runs ended, the facility did not simply sit idle for long. In 2009, CACTUS was demolished, and the converted power plant turned telescope was gone from the desert outside Barstow.
Common questions
What was CACTUS the telescope?
CACTUS, short for Converted Atmospheric Cherenkov Telescope Using Solar-2, was a ground-based Air Cherenkov Telescope located outside Daggett, California, near Barstow. It was an observatory created from a former solar power plant.
How was CACTUS in California created from Solar Two?
CACTUS was created by converting Solar Two, a solar power plant outside Daggett, California, into an observatory. The conversion began in 2001.
When did the CACTUS telescope start and stop observing?
The first astronomical observations at CACTUS started in the fall of 2004. Its last observing runs took place in November 2005.
Why did the CACTUS observatory shut down?
CACTUS shut down because funds for observational operations from the National Science Foundation were no longer available. Without that support, observing ended after November 2005.
Who operated and owned the CACTUS telescope?
CACTUS was operated by the University of California, Davis. The facility was owned by Southern California Edison.
What happened to the CACTUS telescope after it closed?
The CACTUS facility was demolished in 2009.