Progress with the Prime focus spectrograph for the Subaru Telescope: A massively multiplexed optical and near-infrared fiber spectrograph

Hajime Sugai, Naoyuki Tamura, Hiroshi Karoji, Atsushi Shimono, Naruhisa Takato, Masahiko Kimura, Youichi Ohyama, Akitoshi Ueda, Hrand Aghazarian, Marcio V. De Arruda, Robert H. Barkhouser, Charles L. Bennett, Steve Bickerton, Alexandre Bozier, David F. Braun, Khanh Bui, Christopher M. Capocasale, Michael A. Carr, Bruno Castilho, Yin Chang ChangHsin Yo Chen, Richard C.Y. Chou, Olivia R. Dawson, Richard G. Dekany, Eric M. Ek, Richard S. Ellis, Robin J. English, Didier Ferrand, Décio Ferreira, Charles D. Fisher, Mirek Golebiowski, James E. Gunn, Murdock Hart, Timothy M. Heckman, Paul T.P. Ho, Stephen Hope, Larry E. Hovland, Shu Fu Hsu, Yen Sang Hu, Pin Jie Huang, Marc Jaquet, Jennifer E. Karr, Jason G. Kempenaar, Matthew E. King, Olivier Le Fèvre, David Le Mignant, Hung Hsu Ling, Craig Loomis, Robert H. Lupton, Fabrice Madec, Peter Mao, Lucas S. Marrara, Brice Ménard, Chaz Morantz, Hitoshi Murayama, Graham J. Murray, Antonio Cesar De Oliveira, Claudia M. De Oliveira, Ligia S. De Oliveira, Joe D. Orndorff, Rodrigo De Paiva Vilaça, Eamon J. Partos, Sandrine Pascal, Thomas Pegot-Ogier, Daniel J. Reiley, Reed Riddle, Leandro Santos, Jesulino B. Dos Santos, Mark A. Schwochert, Michael D. Seiffert, Stephen A. Smee, Roger M. Smith, Ronald E. Steinkraus, Laerte Sodré, David N. Spergel, Christian Surace, Laurence Tresse, Clément Vidal, Sebastien Vives, Shiang Yu Wang, Chih Yi Wen, Amy C. Wu, Rosie Wyse, Chi Hung Yan

Research output: Chapter in Book/Report/Conference proceedingConference contribution

5 Scopus citations


The Prime Focus Spectrograph (PFS) is an optical/near-infrared multi-fiber spectrograph with 2394 science fibers, which are distributed in 1.3 degree diameter field of view at Subaru 8.2-meter telescope. The simultaneous wide wavelength coverage from 0.38 μm to 1.26 μm, with the resolving power of 3000, strengthens its ability to target three main survey programs: cosmology, Galactic archaeology, and galaxy/AGN evolution. A medium resolution mode with resolving power of 5000 for 0.71 μm to 0.89 μm also will be available by simply exchanging dispersers. PFS takes the role for the spectroscopic part of the Subaru Measurement of Images and Redshifts (SuMIRe) project, while Hyper Suprime-Cam (HSC) works on the imaging part. HSC's excellent image qualities have proven the high quality of the Wide Field Corrector (WFC), which PFS shares with HSC. The PFS collaboration has succeeded in the project Preliminary Design Review and is now in a phase of subsystem Critical Design Reviews and construction. To transform the telescope plus WFC focal ratio, a 3-mm thick broad-band coated microlens is glued to each fiber tip. The microlenses are molded glass, providing uniform lens dimensions and a variety of refractive-index selection. After successful production of mechanical and optical samples, mass production is now complete. Following careful investigations including Focal Ratio Degradation (FRD) measurements, a higher transmission fiber is selected for the longest part of cable system, while one with a better FRD performance is selected for the fiber-positioner and fiber-slit components, given the more frequent fiber movements and tightly curved structure. Each Fiber positioner consists of two stages of piezo-electric rotary motors. Its engineering model has been produced and tested. After evaluating the statistics of positioning accuracies, collision avoidance software, and interferences (if any) within/between electronics boards, mass production will commence. Fiber positioning will be performed iteratively by taking an image of artificially back-illuminated fibers with the Metrology camera located in the Cassegrain container. The camera is carefully designed so that fiber position measurements are unaffected by small amounts of high special-frequency inaccuracies in WFC lens surface shapes. Target light carried through the fiber system reaches one of four identical fast-Schmidt spectrograph modules, each with three arms. All optical glass blanks are now being polished. Prototype VPH gratings have been optically tested. CCD production is complete, with standard fully-depleted CCDs for red arms and more-challenging thinner fully-depleted CCDs with blue-optimized coating for blue arms. The active damping system against cooler vibration has been proven to work as predicted, and spectrographs have been designed to avoid small possible residual resonances.

Original languageEnglish (US)
Title of host publicationGround-Based and Airborne Instrumentation for Astronomy V
EditorsSuzanne K. Ramsay, Ian S. McLean, Hideki Takami
ISBN (Electronic)9780819496157
StatePublished - 2014
EventGround-Based and Airborne Instrumentation for Astronomy V - Montreal, Canada
Duration: Jun 22 2014Jun 26 2014

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


OtherGround-Based and Airborne Instrumentation for Astronomy V

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


  • Prime Focus Spectrograph (PFS)
  • Schmidt spectrograph
  • Subaru telescope
  • Wide Field Corrector
  • fiber positioner
  • microlens
  • multi-fiber spectroscopy
  • optical/near-infrared


Dive into the research topics of 'Progress with the Prime focus spectrograph for the Subaru Telescope: A massively multiplexed optical and near-infrared fiber spectrograph'. Together they form a unique fingerprint.

Cite this