Occultation event with (20729) 99XS143, event index number 1078
Regions able to see the event: SAmericaN,SAmericaS
Geocentric closest approach at 2025/06/20 23:27:11 UTC
J2000 position of star is 09:39:32.5 +03:28:45
Equinox of date position of star is 09:40:52.0 +03:21:47
Star is 118 degrees from the moon. Moon is 26% illuminated.
Stellar brightness G=15.2, apparent brightess of occulting body is G=16.4
Use an exposure time of 0.40 seconds with the standard RECON-QHY system.
SNR of 5.0 per integration for unocculted signal
Expected flux drop is 75% with SNR of 3.8 for the occulted depth (per occulted point)
Apparent velocity is 27.9 km/sec on the sky relative to the star, or, 23.7 arcsec/hr.
The recommended exposure time corresponds to 11.2 km per image.
The 1-sigma error in the time of the event is 1.6 seconds.
The 1-sigma cross-track error in the shadow position is 40.6 km.
The sky-plane scale is 4234.6 km/arcsec.
Diameter estimates:
48.3 km assuming a 5% albedo, aximum of 1.7 sec for a central chord
19.7 km assuming a 30% albedo, maximum of 0.7 sec for a central chord
Cross-track diameter of 48.3 km used for deployment plan.
Star training set for 20729_99XS143, (2025/06/20 23:27UT) Object RA Dec mag sep mel Regulus 10:09:43.5 +11:50:30 1.3 11.09 121 PPM 156043 09:39:46.9 +04:31:59 4.7 1.20 117 PPM 156066 09:40:59.0 +03:04:44 7.9 0.29 118 PPM 156063 09:40:52.8 +03:22:36 10.2 0.01 118 20729_99XS143 09:40:52.0 +03:21:47 16.4 118 Positions are for equinox of date
Star training set for 20729_99XS143, (2025/06/20 23:27UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 11.09 121 PPM 156043 09:38:27.0 +04:38:56 4.7 1.20 117 PPM 156066 09:39:39.6 +03:11:43 7.9 0.29 118 PPM 156063 09:39:33.4 +03:29:35 10.2 0.01 118 20729_99XS143 09:39:32.5 +03:28:45 16.4 118 Positions are for J2000