Diffuse radio emission in Abell 2256 was detected above 3 σ with DRAO observations at 1420 MHz. The halo size is ~13'×10' (~1h 50 -1) in full extent and is elongated along a position angle of about 112°. The total flux density contained in the halo is 30±10 mJy at 1420 MHz and its spectral index is -2.04±0.04, showing no evidence for steepening up to 1420 MHz. Using the size estimate, yields a more reliable equipartition magnetic field strength which is 0.34(1 + k)2/7 μG. In addition, five new radio sources are identified.

Korea Astronomy Observatory (KAO) recently developed a new model of CCD imaging system for astronomical purpose. This paper presents system structure and electrical circuit descriptions with the performance of the CCD imaging system. The developed system can handle astronomical image acquisition with additional functions of on-chip binning, sub-image acquisition using a SITe 1024×1024 1024×1024 CCD chip. Particularly the controller design of the system allows us great flexibility and versatility with the software system control and it is possible to cope with any format CCDs by any manufactures, in principle. The system performances are derived by mean variance test in our laboratory, which shows that the total system noise 10.5e-(R.M.S), Gain 1.9e-/ ADD, non-linearity 0.37% 0.37%

We have constructed a near-infrared imaging camera which is attached to the prime focus of 105cm Schmidt telescope at Kiso Observatory. The camera is equipped with a 1040×1040 PtSi CSD array developed by Mitsubishi Electric Co. The combination of Kiso Schmidt and the array gives a wide field of view of 18.4'×18.4' with a reasonable spatial resolution of 1.06' /pixel. The system performances of the camera have been evaluated through laboratory and observational tests. Low noise, good cosmetics(no defect pixels), and good stability of the camera system show an excellent performance for astronomical use.

An outline is given of our development of mosaic CCD cameras. Hardware and data reduction software of two operational cameras are described. Scientific objectives of wide-field imaging with the cameras are briefly described.