The ʻŌnohiʻula Prime Focus Spectrograph (PFS) is a wide-field, multi-object spectrograph installed on the Subaru Telescope that began full science operations in March 2025. This instrument can observe approximately 2,400 celestial objects at the same time across a wide field of view. It breaks down the light of each object into a rainbow extending well past the range of human vision, i.e., from the visible to near-infrared
light. ʻŌnohiʻula PFS is one of the world’s most powerful tools for capturing and analyzing light from numerous distant objects simultaneously, making it an exceptional instrument for exploring and characterizing large numbers of distant galaxies.
Join our first live online event with this powerful new instrument and watch real-time observations as scientists collect spectra from distant galaxies through the Shadow the Scientists (StS) program.
Figure 1: A snapshot of a previous StS session on November 15, 2024, on the Subaru Telescope facilitated by Dr. Brian C. Lemaux using MOIRCS. This talk can be viewed on YouTube. (Credit: Shadow the Scientists)
What You Will Experience in This Event
The first StS session featuring ʻŌnohiʻula PFS at the Subaru Telescope will be held on the night of Wednesday, March 11, 2026 from 7:00 to 9:00 p.m. (in Hawai‘i Standard Time). Anyone in the world is welcome to register and participate in this free live session.
During this session, Finn Giddings, a PhD student at the University of Hawaiʻi Institute for Astronomy, and Dr. Brian C. Lemaux, a staff scientist at the Gemini North Telescope, together with members the Charting Cluster Construction with VUDS and ORELSE (C3VO) research team, will introduce their scientific goals and methods. They will use ʻŌnohiʻula PFS to study a large sample of galaxies in some of the largest structures in the early Universe. The primary goal of these observations is to map these immense cosmic structures. The team will also examine how often galaxies in the early Universe interacted and merged. They will examine how such interactions influenced galaxy evolution, including the growth of their supermassive black holes, around 10 billion years ago when the Universe was only 10-20% of its current age. In tandem with previous radio, mid-infrared, and X-ray observations, the team aims to understand the role of galaxy interactions in shaping these structures and driving black hole growth.
Subaru Telescope staff will also present how the
ʻŌnohiʻula PFS was developed, demonstrate how the instrument is operated, and share the meaning of its Hawaiian name, ʻŌnohiʻula.
In addition to watching world-class astronomical observations, participants will have the opportunity to listen to short talks by astronomers, scientists, and telescope operators, and to ask questions during the session. Why not join the StS sessions to remotely experience observations with the Subaru Telescope and to meet and talk with astronomers?
Event Details & Registration
Registration form - Link
* Advance registration is required to participate in this Zoom session.
Date & Time:
Wednesday March 11, 7:00 p.m. – 9:00 p.m. (HST; Hawai‘i Standard Time)
Thursday, March 12, 5:00 a.m. – 7:00 a.m. (UTC; Coordinated Universal Time)
Thursday, March 12, 2:00 p.m. – 4:00 p.m. (JST; Japan Standard Time)
Language: English
Presenters:
From Subaru Telescope Hilo Base Facility
Dr. Brian Lemaux (Gemini-North/NOIRLab), Finn Giddings (Institute for Astronomy, University of Hawai‘i at Mānoa), Dr. Yuki Moritani (Advanced Technology Center, NAOJ), Dr. Kumiko Usuda-Sato (Subaru Telescope, NAOJ)
From Subaru Telescope Summit Facility
TBD
From Other Locations
Dr. Naoyuki Tamura (Subaru Telescope, NAOJ), Dr. Roy Gal (Institute for Astronomy, University of Hawai‘i at Mānoa), Jameeka Marshall (Shadow the Scientists)
* Presenters may change without prior notice.
Two days later, on Friday, March 13, 2026, a StS Japanese/bilingual session will take place with the same instrument and observers. The session will primarily be conducted in Japanese; however, participants are welcome to submit questions and messages in English.
About Shadow the Scientists
Shadow the Scientists (StS) is a program that connects the public to professional scientists in various scientific disciplines, including connections to professional astronomers through observing experiences with world-class telescopes.
This program was launched in 2020 during the COVID pandemic by a researcher at the University of California, Santa Cruz, in collaboration with ‘Ohana Kilo Hoku, a native Hawaiian non-profit organization supporting astronomy and space programs, and other partners. Through the program, researchers invite members of the public to remotely experience observations with the Subaru, Keck, and Gemini North Telescopes near the summit of Maunakea, Hawai‘i, the Lick Observatory in California, and many other telescopes around the world.
Previous session videos, such as observations of distant galaxies using the Subaru Telescope's MOIRCS (November 2024) and direct imaging of exoplanets using SCExAO (February 2026), are available on the StS YouTube channel.
Guidelines for Use