Prime Focus Instrument of Prime Focus Spectrograph for Subaru Telescope

TL;DR

The paper describes the design and components of the Prime Focus Instrument for the Subaru Telescope's Prime Focus Spectrograph, enabling wide-field optical/near-infrared spectroscopy with precise fiber positioning.

Contribution

It introduces the detailed mechanical and optical design of the Prime Focus Instrument, integrating multiple subsystems for the Subaru Telescope's spectroscopic observations.

Findings

Designed a structure with deflections matching the HSC Wide Field Corrector

Integrated fiber positioners, A&G cameras, and telemetry systems

Ensured fiber stability and target accuracy during observations

Abstract

The Prime Focus Spectrograph (PFS) is a new optical/near-infrared multi-fiber spectrograph design for the prime focus of the 8.2m Subaru telescope. PFS will cover 1.3 degree diameter field with 2394 fibers to complement the imaging capability of Hyper SuprimeCam (HSC). The prime focus unit of PFS called Prime Focus Instrument (PFI) provides the interface with the top structure of Subaru telescope and also accommodates the optical bench in which Cobra fiber positioners are located. In addition, the acquisition and guiding (A&G) cameras, the optical fiber positioner system, the cable wrapper, the fiducial fibers, illuminator, and viewer, the field element, and the telemetry system are located inside the PFI. The mechanical structure of the PFI was designed with special care such that its deflections sufficiently match those of the HSC Wide Field Corrector (WFC) so the fibers will stay on targets over the course of the observations within the required accuracy.