Hyper Suprime-Cam: filter exchange unit and shutter

ABSTRACT We have developed a lter exchange unit (FEU) and a shutterof Hyper Suprime-Cam (HSC). FEU consists oftwo parts; the alignment mechanism of the lter in the optical path and a jukebox of the lters. The alignmentmechanism can guarantee 10  m position stability with respect to the focal plane CCDs. On the exchangesequence, a motorized cart grabs and pushes the lter from the jukebox. Each jukebox has 3 slots and we havetwo identical jukeboxes. The operation is fully automated and the entire exchange sequence takes 16 minutes.Also, we developed the focal-plane shutterwith 1,030 mm diameter envelope and 60 mm thickness while having600 mm aperture. We report the detail of design and implementation of the shutterand FEU, and installationprocedure of FEU.Keywords: Hyper Suprime-Cam, Subaru Telescope, lter exchanger, shutter1. INTRODUCTION Hyper Suprime-Cam (HSC) is a new wide eld camera for 8.2 m Subaru Telescope. HSC has 1.5 deg eld ofview which corresponds to about 450 mm diameter focal plane in physical dimension. This makes componentslarger and/or heavier than any prime focus instruments of the Subaru Telescope.