Occultation event with (9142) Rhesus, event index number 4258
Regions able to see the event: Europe
Geocentric closest approach at 2026/09/18 01:11:03 UTC
J2000 position of star is 05:21:04.2 +10:29:10
Equinox of date position of star is 05:22:32.9 +10:30:38
Star is 162 degrees from the moon. Moon is 42% illuminated.
Stellar brightness G=15.8, apparent brightess of occulting body is G=16.4
Use an exposure time of 1.00 seconds with the standard RECON-QHY system.
SNR of 5.4 per integration for unocculted signal
Expected flux drop is 62% with SNR of 3.4 for the occulted depth (per occulted point)
Apparent velocity is 10.4 km/sec on the sky relative to the star, or, 10.0 arcsec/hr.
Position angle of asteroid motion is 115.1 degrees
The recommended exposure time corresponds to 10.4 km per image.
The 1-sigma error in the time of the event is 0.7 seconds.
The 1-sigma cross-track error in the shadow position is 27.6 km.
The sky-plane scale is 3749.1 km/arcsec.
Diameter estimates:
43.7 km assuming a 5% albedo, maximum of 4.2 sec for a central chord
17.8 km assuming a 30% albedo, maximum of 1.7 sec for a central chord
Cross-track diameter of 42.3 km used for deployment plan.
Star training set for 9142_Rhesus, (2026/09/18 01:11UT) Object RA Dec mag sep mel Betelgeuse 05:56:37.1 +07:24:35 0.4 8.97 156 Bellatrix 05:26:33.9 +06:22:18 1.6 4.26 158 18 Ori 05:17:33.3 +11:22:09 5.6 1.50 163 PPM 120842 05:21:53.4 +10:54:55 7.3 0.44 162 PPM 120883 05:23:53.4 +10:35:48 9.0 0.34 162 PPM 120852 05:22:24.4 +10:49:05 10.9 0.31 162 9142_Rhesus 05:22:32.9 +10:30:38 16.4 162 Positions are for equinox of date
Star training set for 9142_Rhesus, (2026/09/18 01:11UT) Object RA Dec mag sep mel Betelgeuse 05:55:10.3 +07:24:26 0.4 8.97 156 Bellatrix 05:25:07.8 +06:20:58 1.6 4.26 158 18 Ori 05:16:04.1 +11:20:29 5.6 1.50 163 PPM 120842 05:20:24.5 +10:53:25 7.3 0.44 162 PPM 120883 05:22:24.6 +10:34:22 9.0 0.34 162 PPM 120852 05:20:55.6 +10:47:35 10.9 0.31 162 9142_Rhesus 05:21:04.2 +10:29:10 16.4 162 Positions are for J2000