The Current Status of Prime Focus Instrument of Subaru Prime Focus Spectrograph

TL;DR

The paper reports on the development status of the Prime Focus Instrument for the Subaru Prime Focus Spectrograph, detailing its design, components, and performance to support multi-fiber spectroscopy on the Subaru telescope.

Contribution

It provides an update on the design, integration, and testing of the PFI, highlighting its mechanical structure and component performance for the first time.

Findings

Mechanical structure matches Subaru telescope deflections

Component performance meets design specifications

Integration and testing setup is operational

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 cameras (AGCs), 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's Wide Field Corrector (WFC) so the fibers will stay on targets over the course of the observations within the required accuracy. In this report, the latest status of PFI development will be given including the performance of PFI components, the setup and performance of the integration and testing equipment.