Occultation event with (9142) Rhesus, event index number 4019
Regions able to see the event: SAmericaN
Geocentric closest approach at 2026/08/16 07:28:46 UTC
J2000 position of star is 05:07:20.2 +11:10:32
Equinox of date position of star is 05:08:48.9 +11:12:32
Star is 111 degrees from the moon. Moon is 15% illuminated.
Stellar brightness G=15.8, apparent brightess of occulting body is G=16.5
Use an exposure time of 0.45 seconds with the standard RECON-QHY system.
SNR of 3.3 per integration for unocculted signal
Expected flux drop is 67% with SNR of 2.2 for the occulted depth (per occulted point)
Apparent velocity is 24.0 km/sec on the sky relative to the star, or, 21.2 arcsec/hr.
Position angle of asteroid motion is 95.0 degrees
The recommended exposure time corresponds to 10.8 km per image.
The 1-sigma error in the time of the event is 0.1 seconds.
The 1-sigma cross-track error in the shadow position is 28.5 km.
The sky-plane scale is 4082.8 km/arcsec.
Diameter estimates:
43.7 km assuming a 5% albedo, maximum of 1.8 sec for a central chord
17.8 km assuming a 30% albedo, maximum of 0.7 sec for a central chord
Cross-track diameter of 42.3 km used for deployment plan.
Star training set for 9142_Rhesus, (2026/08/16 07:29UT) Object RA Dec mag sep mel Aldebaran 04:37:27.1 +16:33:38 0.8 9.30 119 Bellatrix 05:26:33.6 +06:22:18 1.6 6.53 107 16 Ori 05:10:47.6 +09:51:42 5.4 1.43 111 PPM 120627 05:09:14.8 +10:55:42 7.2 0.30 111 PPM 120611 05:08:24.2 +11:01:51 10.0 0.20 111 9142_Rhesus 05:08:48.9 +11:12:32 16.5 111 Positions are for equinox of date
Star training set for 9142_Rhesus, (2026/08/16 07:29UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 9.30 119 Bellatrix 05:25:07.8 +06:20:58 1.6 6.53 107 16 Ori 05:09:19.7 +09:49:46 5.4 1.43 111 PPM 120627 05:07:46.2 +10:53:43 7.2 0.30 111 PPM 120611 05:06:55.6 +10:59:50 10.0 0.20 111 9142_Rhesus 05:07:20.2 +11:10:32 16.5 111 Positions are for J2000