Integration and testing of off-axis freeform three-mirror system K-DRIFT Generation 1 (Invited Paper)

We are under testing the KASI Deep Rolling Imaging Fast Telescope Generation 1 (K-DRIFT G1) using an interferometer and flat mirror at 633 nm. The telescope is a confocal off-axis freeform three-mirror system designed for the detection of extremely low surface brightness structures in the sky. The optical specifications of the K-DRIFT G1 are as follows: the entrance pupil diameter is 300 mm, the focal ratio is 3.5, and the field of view is 4.43° × 4.43°. During the integration stage, we used a coordinate measuring machine to measure the positions of the mirrors, flexures, and bezels within a tolerance range. Following the system integration, we are currently measuring wavefront errors at several edge fields using an interferometer at 633 nm. In this paper, we briefly present the current status of the K-DRIFT G1 and the future plans for the project.