Antarctic Tianmu Staring Observation Project II: Data reduction and preliminary results

The Antarctic Tianmu Staring Observation Program (ATSOP) is a time-domain optical sky survey project carried out in Antarctica, featuring large sky coverage, high-cadence sampling, and long-period staring. It aims to fill the gaps in China's observation sky areas and observation modes for the southern hemisphere. At present, we have successfully developed an 18-cm aperture Antarctic Tianmu prototype (AT-Proto). It has been deployed at Zhongshan Station in Antarctica for two consecutive years of trouble-free observations, during which more than 300,000 original images were obtained. This paper systematically outlines the commissioning data of AT-Proto in 2023, the primary data processing pipeline, and preliminary data products. The core pipeline encompasses four key stages: data preprocessing, instrumental effect correction, astrometric solution, and full-field stellar photometry. In this work, we release the 2023 AT-Proto data products, which specifically include reduced image data and a photometric catalog. Preliminary analyses demonstrate the robust performance of the AT-Proto Observing System, with an average photometric precision of 0.05 mag. For a 30-second exposure, the limiting magnitude in the G-band reaches 15.00 mag. Additionally, with Gaia Data Release 3 as the reference catalog, the astrometric precision—quantified by the root mean square (RMS) of position errors—is measured to be approximately less than 2 arcsec, fully validating the system’s observational capabilities.