Occultation event with (21601) 98XO89, event index number 942
Regions able to see the event: SAmericaN
Geocentric closest approach at 2025/05/02 23:14:03 UTC
J2000 position of star is 10:55:07.9 -17:17:29
Equinox of date position of star is 10:56:22.9 -17:25:36
Star is 64 degrees from the moon. Moon is 33% illuminated.
Stellar brightness G=15.8, apparent brightess of occulting body is G=15.3
Use an exposure time of 1.45 seconds with the standard RECON-QHY system.
SNR of 6.6 per integration for unocculted signal
Expected flux drop is 38% with SNR of 2.5 for the occulted depth (per occulted point)
Apparent velocity is 10.3 km/sec on the sky relative to the star, or, 11.4 arcsec/hr.
Position angle of asteroid motion is 101.6 degrees
The recommended exposure time corresponds to 14.9 km per image.
The 1-sigma error in the time of the event is 1.9 seconds.
The 1-sigma cross-track error in the shadow position is 37.7 km.
The sky-plane scale is 3264.6 km/arcsec.
Diameter estimates:
60.0 km assuming a 5% albedo, aximum of 5.8 sec for a central chord
24.5 km assuming a 30% albedo, maximum of 2.4 sec for a central chord
Cross-track diameter of 60.0 km used for deployment plan.
Star training set for 21601_98XO89, (2025/05/02 23:14UT) Object RA Dec mag sep mel Regulus 10:09:43.1 +11:50:33 1.3 31.46 37 4Gam Crv 12:17:06.8 -17:40:57 2.6 19.24 79 PPM 223760 11:00:46.2 -16:29:24 5.3 1.41 64 PPM 223690 10:58:00.9 -17:35:20 8.1 0.42 64 PPM 223649 10:56:18.0 -17:17:16 9.6 0.14 63 21601_98XO89 10:56:22.9 -17:25:36 15.3 64 Positions are for equinox of date
Star training set for 21601_98XO89, (2025/05/02 23:14UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 31.46 37 4Gam Crv 12:15:48.1 -17:32:30 2.6 19.24 79 PPM 223760 10:59:30.8 -16:21:13 5.3 1.41 64 PPM 223690 10:56:45.9 -17:27:11 8.1 0.42 64 PPM 223649 10:55:03.0 -17:09:08 9.6 0.14 63 21601_98XO89 10:55:07.9 -17:17:29 15.3 64 Positions are for J2000