The interactive map below shows our current prediction for the occultation by (21900) Orus on 2024 January 5 UT. The prediction is based on a Gaia eDR3 position for the star, corrected for parallax and proper motion, and the v20230506022620 orbit estimate for Orus, which is derived from orus_20221130a.bsp. This ephemeris has a 1-sigma crosstrack uncertainty of 10.0 km and a 1-sigma downtrack uncertainty of 0.1 sec for this event (these are placeholder values).
The geocentric mid-time of the event is 11:15:01.3 UT. The J2000 star position is RA 07:00:15.2 (7.0042166), Dec +18:04:09 (18.069128), and its magnitude is 14.17. Orus is moving at 16.9 km/s with respect to the star and its diameter is estimated to be 60.5 km, so central chords are expected to last 3.6 seconds.
At the time of the occultation, the target star will be 104.8 degrees from the (37% illuminated) Moon. The predicted magnitude of Orus is 16.42, so it will be 7.9 times fainter than the star it is occulting.
Of-date coordinates for the target star on event night are RA 07:01:39.1 (7.0275278), Dec +18:02:02 (18.033889).