Occultation event with (9142) Rhesus, event index number 1655
Regions able to see the event: SAmericaN
Geocentric closest approach at 2025/12/08 05:08:09 UTC
J2000 position of star is 02:43:12.3 -00:05:52
Equinox of date position of star is 02:44:32.0 +00:00:40
Star is 84 degrees from the moon. Moon is 85% illuminated.
Stellar brightness G=15.8, apparent brightess of occulting body is G=15.7
Use an exposure time of 0.90 seconds with the standard RECON-QHY system.
SNR of 5.1 per integration for unocculted signal
Expected flux drop is 48% with SNR of 2.5 for the occulted depth (per occulted point)
Apparent velocity is 11.3 km/sec on the sky relative to the star, or, 13.1 arcsec/hr.
Position angle of asteroid motion is 93.8 degrees
The recommended exposure time corresponds to 10.2 km per image.
The 1-sigma error in the time of the event is 0.5 seconds.
The 1-sigma cross-track error in the shadow position is 27.4 km.
The sky-plane scale is 3102.0 km/arcsec.
Diameter estimates:
43.7 km assuming a 5% albedo, maximum of 3.9 sec for a central chord
17.8 km assuming a 30% albedo, maximum of 1.6 sec for a central chord
Cross-track diameter of 42.3 km used for deployment plan.
Star training set for 9142_Rhesus, (2025/12/08 05:08UT) Object RA Dec mag sep mel Aldebaran 04:37:24.7 +16:33:33 0.8 32.37 52 Menkar 03:03:38.3 +04:11:24 2.5 6.34 78 82Del Cet 02:40:48.9 +00:26:20 4.1 1.02 85 PPM 145822 02:43:19.0 +00:39:36 8.2 0.72 84 PPM 175175 02:44:56.6 -00:14:09 9.1 0.27 84 PPM 175172 02:44:05.7 +00:05:10 11.1 0.13 84 9142_Rhesus 02:44:32.0 +00:00:40 15.7 84 Positions are for equinox of date
Star training set for 9142_Rhesus, (2025/12/08 05:08UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 32.37 52 Menkar 03:02:16.8 +04:05:21 2.5 6.34 78 82Del Cet 02:39:29.0 +00:19:42 4.1 1.02 85 PPM 145822 02:41:59.0 +00:33:02 8.2 0.72 84 PPM 175175 02:43:36.9 -00:20:41 9.1 0.27 84 PPM 175172 02:42:46.0 -00:01:23 11.1 0.13 84 9142_Rhesus 02:43:12.3 -00:05:52 15.7 84 Positions are for J2000