Tomo-e Gozen is an optical wide-field video observation system composed of a mosaic CMOS camera on the 1.05 m Kiso Schmidt telescope, real-time data analysis software, and automated operation software. Consecutive images at 2 fps with a field-of-view of 20 deg2 are obtained with 84 chips of CMOS image sensors. Produced data of 30 TByte/night are processed by advanced data science methods in real time. A high-speed data acquisition capability of CMOS image sensor enables a quick scan of the sky as well as a high-speed monitoring with sub-sec time resolution. Monochromatic all-sky video-survey of 7,000 deg2 and high-cadence video-survey of 2,000 deg2 are now ongoing. When receiving alerts of gravitational wave events, automated follow-up observations of a few 100 deg2 start quickly. The high-speed observation capability with precise timestamps achieved by GPS allows us to carry out simultaneous monitoring of short time-scale variables with X-ray and radio telescopes. The high-speed, high-cadence, and wide-field observations with Tomo-e Gozen will open new windows for astronomy on short time-scale phenomena including faint meteors, near-earth asteroids, stellar occultations, early-phase supernovae, black hole binaries, optical counterparts of gravitational wave sources and FRBs, and unknown flashes in the Universe.


Kiso Schmidt telescope
Kiso Schmidt telescope

Wide-field telescope (Deff = 1.05 m, f/3.1)

Tomo-e Gozen camera
Tomo-e Gozen camera

Wide-field CMOS camera covering 20 deg2 sky.


Wide field

20 deg2 sky covered by 190 Mpix CMOS camera

High speed

2 fps (max) in full-frame, 160 fps (max) in partial-frame

High time accuracy

Absolute time accuracy of 0.2 msec achieved by GPS

Big data

30 TB every night, processed by advanced data science methods


Video survey

18 frames at 2 fps, 17 mag depth per frame

Quick scan

7,000 deg2 sky (elv > 35 deg) in 2.5 hours


Quick follow-ups of gravitational wave and cosmic neutrino events

Simultaneous monitoring

High-speed observations with X-ray and radio telescopes


Fast moving objects

Near earth asteroids, faint meteors, artificial satellites, space debris


Early phase supernovae, optical counterparts of gravitational waves, stellar flares, transit of exoplanets, outbursts of comets

Sec-to-msec scale events

Blackhole binaries, dwarf novae, spinning compact objects, stellar occultations by the Kuiper belt objects


Optical counterparts of gamma-ray bursts and FRBs, unknown flash events.



Kiso Observatory, Institute of Astronomy, School of Science, the University of Tokyo

10762-30, Mitake, Kiso-machi, Kiso-gun, Nagano 397-0101, Japan