The ProtoDESI experiment was designed to answer the question: Can DESI align its optical fibers with the targets using robotic positioners, and keep them aligned for the duration of a DESI exposure?
The answer: Yes. ProtoDESI demonstrated the successful performance of the robotic positioners and alignment system.
ProtoDESI is a subset of DESI subsystems. It was built to operate with a simplified prime focus instrument, a Fiber View Camera (FVC) for positioning feedback, Telescope Control System (TCS), and Instrument Control System (ICS). Rather than measuring the output of a 50-meter fiber cable with DESI’a spectrographs, ProtoDESI confirmed fiber pointing and stability with a fiber photometry camera (FPC) that imaged the ends of the short 3-meter fibers mounted on the prime focus instrument. The success of ProtoDESI relied heavily on the interaction of its hardware and software, and on the careful translation between focal plane coordinates and target locations. ProtoDESI was mounted to the Mayall telescope from August 15 to September 30, 2016.