OT 060420: A Seemingly Optical Transient Recorded by All‐Sky Cameras

We report on a ∼5th magnitude flash detected for approximately 10 minutes by two CONCAM all‐sky cameras located in Cerro Pachón, Chile, and La Palma, Spain. A third all‐sky camera, located in Cerro Paranal, Chile, did not detect the flash, and therefore we suggest that the flash was a series of cosmic‐ray hits, meteors, or satellite glints. Another proposed hypothesis is that the flash was an astronomical transient with variable luminosity. In this paper, we discuss bright optical transient detection using fish‐eye all‐sky monitors, analyze the apparently false‐positive optical transient, and propose possible causes to false optical transient detection in all‐sky cameras.