Occultation event with (12126) 99RM11, event index number 4137
Regions able to see the event: US,RECON
Geocentric closest approach at 2026/08/31 12:24:56 UTC
J2000 position of star is 05:11:54.2 +24:56:57
Equinox of date position of star is 05:13:32.4 +24:58:47
Star is 60 degrees from the moon. Moon is 88% illuminated.
Stellar brightness G=14.1, apparent brightess of occulting body is G=16.3
Use an exposure time of 0.30 seconds with the standard RECON-QHY system.
SNR of 9.7 per integration for unocculted signal
Expected flux drop is 88% with SNR of 8.6 for the occulted depth (per occulted point)
Apparent velocity is 16.4 km/sec on the sky relative to the star, or, 13.7 arcsec/hr.
Position angle of asteroid motion is 81.7 degrees
The recommended exposure time corresponds to 4.9 km per image.
The 1-sigma error in the time of the event is 0.4 seconds.
The 1-sigma cross-track error in the shadow position is 28.1 km.
The sky-plane scale is 4304.8 km/arcsec.
Diameter estimates:
56.5 km assuming a 5% albedo, maximum of 3.5 sec for a central chord
23.1 km assuming a 30% albedo, maximum of 1.4 sec for a central chord
Cross-track diameter of 53.2 km used for deployment plan.
Star training set for 12126_99RM11, (2026/08/31 12:25UT) Object RA Dec mag sep mel Aldebaran 04:37:27.2 +16:33:39 0.8 11.91 52 Alnath 05:27:58.8 +28:37:39 1.6 4.87 64 103 Tau 05:09:44.3 +24:17:52 5.3 1.10 59 PPM 094178 05:14:41.2 +24:25:35 8.4 0.61 60 PPM 094145 05:12:28.0 +24:54:03 10.0 0.26 60 PPM 094164 05:13:21.3 +24:47:54 10.1 0.19 60 12126_99RM11 05:13:32.4 +24:58:47 16.3 61 Positions are for equinox of date
Star training set for 12126_99RM11, (2026/08/31 12:25UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 11.91 52 Alnath 05:26:17.6 +28:36:22 1.6 4.87 64 103 Tau 05:08:06.6 +24:15:54 5.3 1.10 59 PPM 094178 05:13:03.4 +24:23:48 8.4 0.61 60 PPM 094145 05:10:49.8 +24:52:11 10.0 0.26 60 PPM 094164 05:11:43.2 +24:46:04 10.1 0.19 60 12126_99RM11 05:11:54.2 +24:56:57 16.3 60 Positions are for J2000