Okayama Astrophysical Observatory Wide-Field Camera

摘要

We report on the development of a wide-field near-infrared (0.9-2.5 mu m) camera built as a renewal of the existing classical Cassegrain 0.91m telescope at Okayama Astrophysical Observatory. The optics system was replaced with fast hybrid optics (f/2.5) composed of forward Cassegrain optics and quasi-Schmidt optics, which results in an effective image circle of 52mm diameter on the focal plane. The new camera, called the Okayama Astrophysical Observatory Wide-Field Camera (OAOWFC), has imaging capabilities in the Y, J, H, and K-s bands over a field of view of 0.degrees 47 x 0.degrees 47 with a HAWAII-1 HgCdTe PACE focal plane array. The primary purpose of OAOWFC is to search for variability in the Galactic plane in the K-s band and to promptly follow up transients. We have demonstrated a photometric repeatability of 2% in the densest field in the northern Galactic plane and successfully discovered previously unreported variable stars. The observations of OAOWFC are fully autonomous, and we started scientific operations in 2015 April.