This video captures the scene of the ultra-wide field of view camera Hyper Suprime-Cam (HSC) being installed at the Subaru Telescope prime focus. HSC, which has been prepared and standing by on the TUE (Top Unit Exchanger) Floor behind the wall on the left, is gripped by the yellow Top Unit Exchanger, moved to the prime focus, and installed on the telescope. Specifically, this video was taken during the first test observation. So work proceeds carefully, confirming each step. Including the electrical connections and such, the entire job took 5 hours.

White-Knuckle HSC Installation Work

The Subaru Telescope can have an observational instrument installed directly at its prime focus, or it can have a secondary mirror installed to direct the light to a different focus. But installing HSC is a job requiring great care. Having arrived at the prime focus, the Top Unit Exchanger must conduct connections and installation while lowering HSC’s lens 1.5 meter down through the Top Ring (1 meter diameter ring installation interface). With only 15 millimeter clearance on each side, it is necessary to check the relative positions as installation proceeds (the part in the video between 35 seconds and the 1 minute mark). Moreover, the prime focus is over 20 meters above the floor. Highly skilled specialists work with life-lines attached, but it is dangerous work where you can’t lose concentration for a moment.

Text by: Yutaka Komiyama (Subaru Telescope)
Translation by: Ramsey Lundock (NAOJ)