Development of mid-infrared spectrometer with an image slicer (MIRSIS) for ground-based astronomy: developing optical and mechanical mounts

Mid-Infrared Spectrometer with an Image Slicer (MIRSIS) is a 10micron band spectrometer for ground-based observations. Based on the optical design reported in Okamoto et al. (2006), we recently developed most of optical elements and their mounts. There, we adopted designs based on an ultra-precision cut for the slice mirrors and the pupil mirrors. We also designed and partly manufactured the optical parts with switching/adjusting mechanism with cryogenic step motors. Since MIRSIS has a very complicated stereoscopic configuration of optical elements, we developed a method to adjust the optical alignment where relative positional markers and a three-dimensional measuring system are combined. We confirmed that we can achieve position and angular adjustment with error down to 0.1mm and 0.05degree through alignment test with a pair of mirrors.