We developed an atmospheric gas absorption table for the Advanced Himawari Imager (AHI) based on the correlated k-distribution (CKD) method with an optimization method, which was used to determine quadrature weights and abscissas. We incorporated the table and band information of the AHI into a multi-purpose atmospheric radiative transfer package, RSTAR. We updated the package so that users could easily specify the satellite and band number. Use of this update made it possible to carry out calculations rapidly and accurately using the optimized CKD method. RSTAR is easy for beginners to use and facilitates comparison of results. Cloud retrieval tests using different numbers of quadrature points showed that cloud retrievals could be significantly affected by the CKD model's accuracy.