Oral Presentation
Software Development of Fiber Positioning Sequencer for Prime Focus Spectrograph of Subaru Telescope
Presenter: Chi-Hung Yan (ASIAA)
The Prime Focus Spectrograph (PFS) is an innovative optical/near-infrared multi-fiber spectrograph designed to operate at the prime focus of the 8.2m Subaru telescope. With its 2394 fibers in a 1.3-degree diameter field, PFS significantly complements the imaging capabilities of Hyper SuprimeCam (HSC). At the core of PFS lies the Prime Focus Instrument (PFI), responsible for providing the interface with the telescope's top structure while accommodating the optical bench that houses the vital Cobra fiber positioners. The Fiber Positioning System (FPS) represents an automated control system designed to command the precise positioning of these science fibers during astronomical observations.
To accomplish this intricate task, FPS controls the Metrology Camera System (MCS) and the Cobra Controlling System (cobraCharmer), effectively measuring fiber positions and moving them to predetermined targets through iterations. The requirements of FPS includes continuous operations for 14 hours each night, ensuring the fiber positioning sequence is executed every 15 minutes with a success rate of 95% or higher for each alignment within a 120-second timeframe. For every observation, FPS receives an observation target list from the Integrated Instrument Control System (IIC) of the telescope. Subsequently, FPS commands the Metrology Camera System (MCS) and MPS (Motor Positioning System) to guide the Cobras and capture images for precise centroid measurements of the fiber locations. The MCS efficiently measures the position of each fiber. The actual fiber movements are orchestrated by MPS, facilitated through FPS using TCP/IP sockets.
As an additional feature, FPS maintains a comprehensive database encompassing the Cobra movement history and fiber locations for every centroid measurement. This valuable information is utilized to generate a motor map, which is then fed back into the FPS system, thus enhancing the performance of Cobra movements. In this talk, we will present the latest progress in the development of the FPS system and discuss its calibration and performance characteristics.
asiaa.sinica.edu.tw