Occultation event with (20729) 99XS143, event index number 1028
Regions able to see the event: SAmericaN
Geocentric closest approach at 2025/06/04 01:37:00 UTC
J2000 position of star is 09:30:22.0 +04:16:21
Equinox of date position of star is 09:31:41.6 +04:09:35
Star is 32 degrees from the moon. Moon is 59% illuminated.
Stellar brightness G=16.0, apparent brightess of occulting body is G=16.3
Use an exposure time of 0.55 seconds with the standard RECON-QHY system.
SNR of 3.0 per integration for unocculted signal
Expected flux drop is 57% with SNR of 1.7 for the occulted depth (per occulted point)
Apparent velocity is 21.5 km/sec on the sky relative to the star, or, 19.1 arcsec/hr.
The recommended exposure time corresponds to 11.8 km per image.
The 1-sigma error in the time of the event is 2.1 seconds.
The 1-sigma cross-track error in the shadow position is 38.7 km.
The sky-plane scale is 4061.1 km/arcsec.
Diameter estimates:
48.3 km assuming a 5% albedo, aximum of 2.2 sec for a central chord
19.7 km assuming a 30% albedo, maximum of 0.9 sec for a central chord
Cross-track diameter of 48.3 km used for deployment plan.
Star training set for 20729_99XS143, (2025/06/04 01:37UT) Object RA Dec mag sep mel Regulus 10:09:43.4 +11:50:31 1.3 12.15 24 PPM 156043 09:39:46.8 +04:32:00 4.7 2.05 30 PPM 155918 09:32:25.3 +02:58:01 7.4 1.21 32 PPM 155947 09:34:07.1 +03:34:52 8.9 0.84 31 PPM 155914 09:32:03.8 +03:56:57 10.2 0.23 32 20729_99XS143 09:31:41.6 +04:09:35 16.3 32 Positions are for equinox of date
Star training set for 20729_99XS143, (2025/06/04 01:37UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 12.15 24 PPM 156043 09:38:27.0 +04:38:56 4.7 2.05 30 PPM 155918 09:31:06.0 +03:04:47 7.4 1.21 32 PPM 155947 09:32:47.7 +03:41:41 8.9 0.84 31 PPM 155914 09:30:44.2 +04:03:43 10.2 0.23 32 20729_99XS143 09:30:22.0 +04:16:21 16.3 32 Positions are for J2000