As of September 9, CNEOS has the close approach of 2024 ON on 2024-Sep-17 10:19±<00:01 UT at a distance of 0.00668 AU moving with V Relative=8.87 km/sec, H=20.5 magnitude, diameter 210 m - 470 m and 'Rarity'=3. As of 2024 Sep 9 there is a 44 day observation arc, the Condition Code=6 and Earth MOID=0.00311429 AU. The solution date was 2024-Sep-09 06:21:56 PDT. The initial reported observation was by ATLAS-MLO, Mauna Loa on 2024-07-27. This NEO is on the MPC's list of Potentially Hazardous Asteroids (PHA).
Using MPC's elements for 2024 Sep 9 0000 UT, ST4.1.11.10 Visual Pro predicts that this NEO will reach a peak brightness of 12.0 magnitude on 2024 Sep 17 at 0600 EDT when the MP will be traveling through Indus at 107"/minute, but below the horizon in Columbus, Ohio. Close approach is predicted (to the nearest hour) on 2024 Sep 17 at 0600 EDT as well. This NEO is predicted to be brighter than 16 magnitude from Sep 10 (15.8 magnitude in Ophiuchus, 4.25"/minute, 0.03 AU distant) to Sep 23 (15.8 magnitude in Lepus 4.71"/minute, 0.03 AU distant). The close approach is best observed from the southern hemisphere, but the NEO should be visible from the northern hemisphere before and after close approach.
Here's the Object Info dialog for this NEO:
Since the close approach distance is only 0.00668 AU, perturbations will be an issue. Orbital elements should be downloaded near the day of observation for best results.
Good hunting,
Phil S.
Edit: Just noticed that on 2024 Sep 15 ~1800 Brisbane time, 2024 ON will pass through the open cluster M25 in Sagittarius then on Sep 16 ~0300 it will pass within 1° of the globular cluster M22.
Using MPC's elements for 2024 Sep 9 0000 UT, ST4.1.11.10 Visual Pro predicts that this NEO will reach a peak brightness of 12.0 magnitude on 2024 Sep 17 at 0600 EDT when the MP will be traveling through Indus at 107"/minute, but below the horizon in Columbus, Ohio. Close approach is predicted (to the nearest hour) on 2024 Sep 17 at 0600 EDT as well. This NEO is predicted to be brighter than 16 magnitude from Sep 10 (15.8 magnitude in Ophiuchus, 4.25"/minute, 0.03 AU distant) to Sep 23 (15.8 magnitude in Lepus 4.71"/minute, 0.03 AU distant). The close approach is best observed from the southern hemisphere, but the NEO should be visible from the northern hemisphere before and after close approach.
Here's the Object Info dialog for this NEO:
Since the close approach distance is only 0.00668 AU, perturbations will be an issue. Orbital elements should be downloaded near the day of observation for best results.
Good hunting,
Phil S.
Edit: Just noticed that on 2024 Sep 15 ~1800 Brisbane time, 2024 ON will pass through the open cluster M25 in Sagittarius then on Sep 16 ~0300 it will pass within 1° of the globular cluster M22.