ʻŌnohiʻula Prime Focus Spectrograph (PFS)

Information

Call for Proposals for S26B

   The principal investigator (PI) must read Observations page and follow the instructions for observation planning and proposal preparations.

   Telescope downtime for the S26B period is expected to be about 2.5 months in mid-Nov to February . Please make observation plans with careful checking of target visibility in the autumn and winter seasons.

Updates for CfP S26B
   Priority of Flux Standard stars and its data release (S26B)
   Observation and Proposal Preparation Revised some important explanation for Queue and Classical modes.

Information for S26A observers

   Important notice for S26A: SM2 NIR (N2) Detector Replacement and Suspension in S26A
   PFS DRP Tutorial: Visit for details on PFS Data Reduction Pipeline.

Introduction

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The ʻŌnohiʻula Prime Focus Spectrograph (PFS) is a spectrograph system mounted at the prime focus of the Subaru telescope. Four identical spectrograph modules are fed by a total of ~2400 fibres, allowing for simultaneous observations of ~2400 targets within a very wide-field (~1.25 deg²). The spectra cover a wide wavelength range from 0.38 μm to 1.26 μm, with a resolving power of approximately 2,300 in the blue channel, and up to 5,000 in the red channel (medium resolution mode).

The PFS instrument has the Hawaiian name, ʻŌnohiʻula

See also the announcement in Subaru topics and PFS Blog.
The pronunciation of ʻŌnohiʻula is "oh-no-he-oo-lah" in the phonetic spelling for English speakers, and "オーノヒウラ" in the phonetic spelling with Japanese Katakana. Click to hear 'Ōnohi'ula
See also ʻŌnohiʻula PFS Usage and Citation Guide (Jan-10-2026).

In principle, observations will be conducted in queue mode, to maximize the observing efficiency by optimizing the fiber positions. Classical mode observations can be requested for observations that require exposure times other than 15 min, specific configuration of pointing centers, or time-critical execution.

Please review the Observations page carefully when planning to observe with PFS. For proposal preparation, please also refer to Getting Started Manual.

Instrument

• Overview
• Basic instrument parameters
• System efficiency
• FITS header
• Publications

Observations

• Observation modes
  • Queue mode
  • Classical mode
  • Target of Opportunity (ToO)
  • Fillers
• Proposal and Observation preparations
  • Tutorial materials
  • Applicable to all modes
    • Reference arm specification for targets focused on near-Infrared arm
    • Requirements on uploading multiple target list
  • Queue mode preparations
  • Classical mode preparations
    • Constraints on Classical Modes
  • ToO preparations
  • Community filler preparations
  • Template of Technical Justification
• Additional information
• Relevant documents
• Tools
  • PFS Spectral Simulator
  • PFS Target Uploader

Data access and reduction

• Queue progress
• Data access
• Data reduction pipeline
• PFS science platform
• PFS DRP Tutorial

Current status

• Status of instrument
• Status of DRP development
• Performance verification

Links

• PFS Project
• Proposal of PFS Subaru Strategic Program (SSP)
• Getting Started Manual for preparation of PFS proposal.
• Tutorial of PFS Target Uploader
• Tutorial of PFS Spectral Simulator (ETC)

Contact

PFS observation helpdesk

Questions regarding proposal and observation preparation:

Some of our helpdesk members are non-Japanese speakers. In principle, please ask your questions in English. Responses to questions in Japanese may take some extra time.