The interactive map below shows our current prediction for the stellar occultation by (21900) Orus on 2020 October 21 UT. The prediction is based on a Gaia DR2 position for the star, corrected for parallax and proper motion, and the v20200831220404 orbit estimate for Orus. The 1-sigma cross-track uncertainty is 11.1 km, which accounts for uncertainties in both the orbit prediction and the stellar position.
Geocentric mid-time of the event is 06:14:51 UT. Star position is RA 23:16:36.7, Dec +06:10:54 (J2000), and its magnitude is 16.95. Orus is moving at 11 km/s with respect to the star and its diameter is estimated to be 51 km, so central chords are expected to last 4.5 seconds. Orus' magnitude is predicted to be 17.0 at event time, so it will be the same brightness as the star.