Engineering observations of MIMIZUKU at Subaru

MIMIZUKU is the 1st-gen. mid-infrared instrument for the TAO 6.5-m telescope being constructed at the Atacama Desert in Chile. Its performance was evaluated through the engineering observations performed at Subaru in 2018. As a result, imaging and low-resolution spectroscopic modes in 7-25 micron wavelengths were confirmed to be fine, although the sensitivity was degraded by detector noise. We also tested the functions of a special optical device called Field Stacker mounted on MIMIZUKU. The device allows us to select and combine two arbitrary observation fields in the telescope field-of-view. By observing a science target and a calibrator with the Field Stacker, we can accurately correct the atmospheric absorption and precisely measure the brightness and spectrum of the target. Through the engineering observations, we confirmed that the Field Stacker improved the photometric stability and the quality of spectrum even in the Q band. We report the results and future plans of MIMIZUKU