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Coolant leakage damages Subaru telescope

A serious incident has been recorded at the Subaru telescope, the National Astronomical Observatory of Japan's flagship observation system located on the US island of Hawaii.

The incident occurred while the telescope was being shut down at the end of the night shift on 2 July. The telescope operator detected an error signal from the top unit of the telescope, which includes the Subaru Prime Focus Camera (Suprime-Cam).

The Telescope Engineering Division found extensive leakage of coolant (ethylene glycol) from the top unit. The leakage affected the top unit itself and Suprime-Cam, down to the tertiary mirror, the primary mirror and some of its actuators, the Faint Object Camera and Spectrograph (FOCAS, a Cassegrain instrument) and its auxiliary optics, and the telescope floor.

Inspections have shown that the spillage was confined to the enclosure itself and did not spread into the environment of the site. However, assessment of the extent of the damage is said to be continuing.

During the clean-up and recovery of equipment, night-time observations as well as daytime summit tours of the Subaru Telescope are temporarily suspended.