Minor Planet Occultations

(15161) 2000 FQ48 on 12 November 2020

Great Shefford was on the edge of the predicted shadow path of Minor Planet (15161) = 2000 FQ48. The maximum duration of the occultation was given as 3.3 seconds if observed on the central line of the shadow, but the track must have been to the west of the prediction because a 3.5 second occultation was observed, allowing a refinement of the asteroid size, to at least 35 km.

The faint line in the gap during the occultation is the trail of a faint star, not the asteroid itself, which at magnitude +17.3 was too faint to record directly on the drift-scan.

Screenshot of drift-scan measurement using Scanalyzer (see page by John Broughton, Reedy Creek Observatory, Australia here). Thin cloud affected the beginning of the exposure, but thanks to the occulted star being bright at magnitude +9.7 it still allowed the start of trail measurement to be well defined.