Occultation event with (9799) Thronium, event index number 3594
Regions able to see the event: Europe,SAfrica
Geocentric closest approach at 2026/04/07 21:17:03 UTC
J2000 position of star is 10:06:42.1 -27:10:53
Equinox of date position of star is 10:07:54.3 -27:18:37
Star is 93 degrees from the moon. Moon is 71% illuminated.
Stellar brightness G=16.8, apparent brightess of occulting body is G=15.0
Use an exposure time of 1.90 seconds with the standard RECON-QHY system.
SNR of 3.0 per integration for unocculted signal
Expected flux drop is 16% with SNR of 0.5 for the occulted depth (per occulted point)
Apparent velocity is 15.5 km/sec on the sky relative to the star, or, 16.4 arcsec/hr.
Position angle of asteroid motion is 149.1 degrees
The recommended exposure time corresponds to 29.4 km per image.
The 1-sigma error in the time of the event is 2.2 seconds.
The 1-sigma cross-track error in the shadow position is 1.3 km.
The sky-plane scale is 3393.4 km/arcsec.
Diameter estimates:
71.1 km assuming a 5% albedo, maximum of 4.6 sec for a central chord
29.0 km assuming a 30% albedo, maximum of 1.9 sec for a central chord
Cross-track diameter of 68.0 km used for deployment plan.
Star training set for 9799_Thronium, (2026/04/07 21:17UT) Object RA Dec mag sep mel Adhara 06:59:39.5 -29:00:34 1.5 41.25 119 Lam Vel 09:08:57.9 -43:32:23 2.2 20.12 92 PPM 257358 10:14:32.1 -27:09:34 6.4 1.48 92 PPM 257231 10:08:42.8 -27:15:52 8.5 0.19 93 9799_Thronium 10:07:54.3 -27:18:37 15.0 93 Positions are for equinox of date
Star training set for 9799_Thronium, (2026/04/07 21:17UT) Object RA Dec mag sep mel Adhara 06:58:37.6 -28:58:19 1.5 41.25 119 Lam Vel 09:07:59.7 -43:25:57 2.2 20.12 92 PPM 257358 10:13:19.3 -27:01:43 6.4 1.48 92 PPM 257231 10:07:30.5 -27:08:07 8.5 0.19 93 9799_Thronium 10:06:42.1 -27:10:53 15.0 93 Positions are for J2000