The interactive map below shows our current prediction for the occultation by (617) Patroclus-Menoetius on 2024 August 11 UT. The prediction is based on a Gaia eDR3 position for the star, corrected for parallax and proper motion, and the v20240425150736 orbit estimate for Patroclus-Menoetius, which is derived from pm_combocloud2_1b_bary.bsp and pm_combocloud2_1b_mutual.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 10:47:31.4 UT. The J2000 star position is RA 01:08:10.1 (1.1361398), Dec -13:06:28 (-13.107781), and its magnitude is 13.39. Patroclus and Menoetius are moving at 5.2 km/s with respect to the star and their diameters are estimated to be 113 and 108 km, respectively, so central chords are expected to last 21.7 seconds for Patroclus and 20.8 seconds for Menoetius.
At the time of the occultation, the target star will be 147.1 degrees from the (39% illuminated) Moon. The system magnitude (Patroclus+Menoetius) is predicted to be 14.85, so it will be 3.8 times fainter than the star it is occulting.
Of-date coordinates for the target star on event night are RA 01:09:23.5 (1.1565278), Dec -12:58:37 (-12.976944).