HinOTORI is a 50cm telescope which is co-constructed and shared by China and Japan. It can image in u’, Rc and Ic bands simultaneously, its main scientific observation targets are gravitational waves (GWs) optical counterparts (OTs). The installation of the telescope has been finished, and the engineering first light observation was carried out in May 2018. This paper will give an overall introduction and parameters of the telescope and then concentrate on a focusing method, which aims at obtaining the best focus position from the fitting equation. The reason of the best position shifting is also discussed.
We developed a new CCD readout system for the Kanata 1.5m telescope in Higashi-Hiroshima Astronomical Observatory, Hiroshima University, Japan, based on the system originally developed by the Kiso Array Controller (KAC) project. In this development we aim at reducing the size and the cost of the system. The system consists of CCD drive circuit, three-order low-pass filters, differential input A/D converter, FPGA, LVDC board, and can be operated by Linux host. We report the current design and performances of this system, and the future work as well. This readout system will be easily applicable to many other astronomical instruments.
WFST is a proposed 2.5m wide field survey telescope intended for dedicated wide field sciences. The telescope is to operate at six wavelength bands (u, g, r, i, z, and w), spanning from 320 to 1028 nm. Designed with a field of view diameter of 3 degree and an effective aperture diameter of 2.29 m, the WFST acquires a total optical throughput over 29.3 m2deg2. With such a large throughput, WFST will survey up to 6000deg2 of the northern sky in multiple colors each night, reaching 23th magnitude for high-precision photometry and astrometry. The optical design is based on an advanced primary-focus system made up of a 2.5 m f/2.48 concave primary mirror and a primary-focus assembly (PFA) consisting of five corrector lenses, atmospheric dispersion corrector (ADC), filters, and the focal-plane instrument. For zenith angles from 0 to 60 degrees, 80% of the polychromatic diffracted energy falls within a 0.35 arcsec diameter. The optical design also highlights an enhanced transmission in the UV bands. The total optical transmission reaches 23.5% at 320 nm, allowing unique science goals in the U band. Other features include low distortion and ease of baffling against stray lights, etc. The focal-plane instrument is a 0.9 gigapixel mosaic CCD camera comprising 9 pieces of 10K×10K CCD chips. An active optics system (AOS) is used to maintain runtime image quality. Various design aspects of the WFST including the optical design, active optics, mirror supports, and the focal-plane instrument are discussed in detail.