Occultation event with (9799) Thronium, event index number 1192
Regions able to see the event: SMexico
Geocentric closest approach at 2025/05/11 01:36:36 UTC
J2000 position of star is 08:22:34.8 -08:48:13
Equinox of date position of star is 08:23:48.5 -08:53:10
Star is 82 degrees from the moon. Moon is 98% illuminated.
Stellar brightness G=16.4, apparent brightess of occulting body is G=15.4
Use an exposure time of 1.00 seconds with the standard RECON-QHY system.
SNR of 3.0 per integration for unocculted signal
Expected flux drop is 28% with SNR of 0.8 for the occulted depth (per occulted point)
Apparent velocity is 19.0 km/sec on the sky relative to the star, or, 17.4 arcsec/hr.
Position angle of asteroid motion is 17.7 degrees
The recommended exposure time corresponds to 19.0 km per image.
The 1-sigma error in the time of the event is 1.8 seconds.
The 1-sigma cross-track error in the shadow position is 25.6 km.
The sky-plane scale is 3918.3 km/arcsec.
Diameter estimates:
70.8 km assuming a 5% albedo, aximum of 3.7 sec for a central chord
28.9 km assuming a 30% albedo, maximum of 1.5 sec for a central chord
Cross-track diameter of 70.8 km used for deployment plan.
Star training set for 9799_Thronium, (2025/05/11 01:37UT) Object RA Dec mag sep mel Sirius 06:46:15.9 -16:45:09 -1.5 25.02 102 15Rho Pup 08:08:37.5 -24:22:44 2.8 15.91 82 PPM 191264 08:24:08.4 -07:37:33 5.8 1.26 82 PPM 191242 08:22:48.6 -08:45:10 7.6 0.28 82 PPM 191256 08:23:43.9 -08:47:35 9.3 0.09 82 9799_Thronium 08:23:48.5 -08:53:10 15.4 81 Positions are for equinox of date
Star training set for 9799_Thronium, (2025/05/11 01:37UT) Object RA Dec mag sep mel Sirius 06:45:07.9 -16:43:28 -1.5 25.02 102 15Rho Pup 08:07:32.5 -24:18:14 2.8 15.91 82 PPM 191264 08:22:54.1 -07:32:35 5.8 1.26 82 PPM 191242 08:21:34.9 -08:40:15 7.6 0.28 82 PPM 191256 08:22:30.1 -08:42:38 9.3 0.09 82 9799_Thronium 08:22:34.8 -08:48:13 15.4 82 Positions are for J2000