A serious hardware incident occurred at the Subaru Telescope during the early morning of Saturday, July 2nd, toward the end of the nighttime observations. Coolant for the auxiliary optics system of the prime focus camera leaked onto the telescope ond flooded the mirror and instruments

Since the cooling system is located at the top ring of the telescope, the coolant’s mixture of water and ethylene glycol not only leaked onto Suprime-Cam but also onto the primary mirror and the Faint Object Camera and Spectrometer (FOCAS, a Cassegrain instrument). Damage assessments and clean-up efforts are ongoing.

Inspections have shown that the spillage is confined to the enclosure itself and did not spread into the environment of the site. The incident did not harm any observatory staff or observers. Nighttime observations and daytime summit tour programs are suspended until further notice.

Souce: Subaru telescope