Gonnessia is a 99-kilometre-wide asteroid orbiting between Mars and Jupiter. Its surface is extremely dark, with an albedo of only three percent.
On 15 August 2020 it occulted the 12th-magnitude star UCAC-399-084279 along a narrow path that crossed Auckland, New Zealand. The background star disappeared for 7.75 seconds as the asteroid passed in front of it.
A captured light curve helps astronomers refine the asteroid's orbit and shape as its shadow crosses Earth at more than 6.4 kilometres per second. Contributing observations to the occultation community adds useful measurements to our knowledge of the Solar System.
I recorded the event through my 120 mm refractor from central Auckland, using 250 ms integration frames, and processed the sequence in Tangra.