50 mm balloon-borne white-light coronagraph: II. Testing and verification of key instrument parameters

This study mainly introduces the experimental verification of the key parameters of a 50-mm balloon-borne white-light coronagraph system mounted on a floating platform. Various testing systems were designed and constructed to test the optical imaging performance, instrument polarization characteristics, vacuum focal length correction, and tracking performance of the rotating platform for the spherical white-light coronagraph. The test results indicate that this white-light coronagraph system has the capability to continuously observe the white-light corona at an altitude of approximately 30 km in the stratosphere. After the overall integration of the white-light coronagraph system, simulated flight tests were conducted. The experiments demonstrated that during a 6-h solar tracking observation, the coronagraph was able to effectively track the observation target and complete the observation tasks. Overall testing indicates that the white-light balloon-borne coronagraph meets the conditions for deployment.