The First Scientific Flight and Observations of the 50 mm Balloon-borne White-light Coronagraph

Abstract A 50 mm balloon-borne white-light coronagraph (BBWLC) to observe white-light solar corona over the altitude range from 1.08 R ⊙ to 1.50 R ⊙ has recently been indigenously developed by Yunnan Observatories in collaboration with Shandong University (in Weihai) and Changchun Institute of Optics, Fine Mechanics and Physics, which will significantly improve the ability of China to detect and measure the inner corona. On 2022 October 4, its first scientific flight took place at the Dachaidan area in Qinghai province of China. We briefly describe the BBWLC mission including its optical design, mechanical structure, pointing system, the first flight and results associated with the data processing approach. Preliminary analysis of the data shows that BBWLC imaged the K-corona with three streamer structures on the west limb of the Sun. To further confirm the coronal signals obtained by BBWLC, comparisons were made with observations of the K-coronagraph of the High Altitude Observatory and the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory. We conclude that BBWLC eventually observed the white-light corona in its first scientific flight.